Yeah, I don't recall there being any grav vehicles in any of the games, but they may exist. Floating robots are a thing mind, so it wouldn't be hard to consider some country producing a grav tank. Come to think of it in the Fallout 3 concept art book there's a floating street cleaner, so let's assume that they applied that technology to military purposes before municiple.

For use in 7TV, here's some draft rules for Radiation and Power Armour. Hopefully not too complex or broken. They aren't as long as they may seem btw, I've just added in notes and future suggestions to clarify things.
RadiationSpecial EffectsPhysicalRad Resistance (x)Rad Resistance (x)may be taken by those cast members with access to Physical special effects. This value may be increased by spending additional points in this effect.
Additionally it may be applied by various pieces of equipment or be inherent to a cast member's profile.
* A list of these will be created later, something similar to the equipment table in the base rules (ie Gas Masks would be “Basic”, Radiation suits would be “Military”, and Power Armour “Advanced”). Though there would be additional sub lists for upgrades beneath each main weapon/armour section, as would there be a “Skill Requirement” field for some items (ie a suit of Salvaged Power Armour would have a strength requirement of 5 due to the great strength needed to wear the armour without aid).
OtherRad Level (x)Certain locations, such as toxic waste piles, nuclear bombs, etc, give off radiation. The level of rads emitted varies between them, from a mild prickling on the skin, to full on barbecue. Designate the radiation level of an object. The immediate 2'' from its central point (or the edges of its largest piece for more sizeable models) are at the Rad Level marked as the “X”. For every 1'' after this point this value decreases by one, until no value remains.
As an example, a Nuclear Bomb sits unexploded in the wastes leaking toxic fluids. It has a Rad Level of 12. 5'' from its central mass this rad level would decrease to 11, 7'' it would be 10, and so on.
*Question, do these values seem too extreme or are they fine? They're there to make particularly dangerous sources of radiation be deadlier than smaller ones. At their current levels it could take a cast member two turns to reach said Nuclear Bomb (6'' move, double to 12'' if they run, but that's still two turns should they need to activate something, and another one as they run full pelt away from the location).
Should a model spend any point of their turn within an area marked with radiation then they must make an immediate defence test at their end of their turn, done with the following modifiers.
*Note for mathematicians: I haven't actually worked out the full range of values for this table. It needs work based on maximum rad resistance levels. The scale as it stands is based around the four levels, with 1 being you're average gas mask, 2 an environmental suit, 3 Power armour/ advanced radiation suits, and 4 Radiation resistant creatures like Super Mutants. So, at Rad Resistance (4) a Super Mutant would need to be in a Rad Level (16) area to suffer the full detrimental effects. 16 may but level 4 Rad Resistance represents a near immunity. 16'd be nuclear weapon going off (Fat Man's would create a similar, but temporary level).
Radiation Level > Effect on Cast Member's Defence
1x cast member's Rad Resistance Level > 0, no Defence test must be made
2x cast member's Rad Resistance Level > -1
3x cast member's Rad Resistance Level > -2
4x cast member's Rad Resistance Level> -3
(that's meant to be a table, but I can't be sodden with the html right now)
Should the cast member's Rad Resistance Level be double the area's Rad Level then they may ignore this test.
Should a model have no levels in Rad Resistance then use the “x” value of the areas's Rad Level for applying the effects on the Cast Member's Defence stat.
For example, a cast member with no Rad Resistance enters a level four rad area. They would be at a -4 for their defence test. However, if a cast member with a Rad Resistance level of 2 enters the same area then they would be at -1 to their defence.
*Rad Level is generated by various things. So it could be the aforementioned pieces of terrain, but also weapons (Fat Man, or perhaps weapons that generate a small amount of rads to the user when fired- like plasma weapons in 40k, they may kill the user if they aren't protected) and creatures (Glowing Ones, animals that have certain attacks). Terrain would form most of the permanent sources of radiation, with the other ones being temporary for the most part (Glowing ones would produce a constant small rad level, but could create a one turn high level rad explosion).
Plus a some of anti-radiation drugs purchasable to cast members (with the quantities being dependent on the category of the table they're in, ie at the “Basic” level a cast member could buy 1 Rad-X, at “Military” they could by 2, and at “Advanced” they could buy 3 (a cast member couldn't buy the same item twice or from different categories)).
EquipmentRad-XSingle use. When used the cast member's Rad Resistance level is boosted by 1 point for two turns (three with the Slow Metabolism effect – to be written later).
RadAwaySingle Use. When used the cast member may half the value (rounding down) of the negative effect upon their defence when making a defence check for being in an irradiated area. Should this value be reduced to 0 then no defence check is required to be made.
As in the above example, if a cast member with a Rad Resistance level of 2 enters the a level four rad area then they would be at -1 to their defence. Should they use some RadAway this value would be halved to -0.5, and so, rounding down, 0. As a result they would not have to make a defence test.
Rad-Purge (not its final name)
Single Use. When used the cast member may ignore the defence test required to be made for spending time in an irradiated area. On the following turn however they're agility, defence and strength are reduced by 1 and move by -2 for the rest of the game.
* This is meant to be an experimental drug, like the one Colonel Autumn uses in Fallout 3. It saves the cast member from extreme radiation, but wrecks their body in the process (well until they can receive proper medical attention after the game). Yes, a cast member could take one of these repeatedly (though only one is purchasable under the “Advanced” section, but they could loot others in game) and wind up with 1 in all their stats.
Power Armour I've also brainstormed some Power Armour rules. My current intentions for their rules would be to provide “Power Armour Training” as the base skill only available to those who have first taken the Military Training skill, before then allowing these cast members to buy a suit of power armour from a list. I haven't thought much on that requirement though, I'm just trying to think of a way to limit the number of users (though I suppose I could remove it and just leave it up to players).
Speial EffectsKnowledgePower Armour TrainingThis effect may only be taken by those who have already chosen the Miltitary Training effect. Models with this effect may chose to equip themselves with one of the various types of Power Armour available to them under the “Advanced” section of the equipment table.
Example Power Armour types (sans ratings costs):
Advanced Power Armour (Enclave/ Vault Tec)
Effects: +1 Str,+2 Def, Body Armour, Rad Resistance (2) ~ 3 with suit and same type of helmet *, Weight Compensation
Pre-War Power Armour (T-45d/ T-51b)
Effects: +1 Str, +2 Def, - 1 Agl, Body Armour, Rad Resistance (2) ~ 3 with suit and same type of helmet*, Weight Compensation
Salvaged Power Armour **
Effects, +2 Def, - 2 Agl, Body Armour, Rad Resistance (2) ~ 3 with suit and same type of helmet* , Slow (May only be worn by cast members with a strength of 5 or higher), Weight Compensation
*This is in here for uniformity, assuming that a suit can't lock in a different type of helmet.
** Salvaged Power Armour wouldn't require Power Armour Training and would be under “Military”. I'm just sticking it in here completeness. It has Weight Compensation due to the wearer's great strength.
This is for the suits, helmets come separately. Models must wear the same type of helmet as their base suit. I may bunk in the helmets with the suits, but I'd rather allow or bareheaded models too.
Advanced Power Armour HelmetEffect: +1 Per, Respirator*, Night Vision
Pre-War Power Armour HelmetEffect: Respirator, Night Vision **
Salvaged Power Armour Helmet ***
Effects, -1 Per, Respirator *(may only be worn by cast members with a strength of 4 or higher)
* Respirator: Has the same effect as a gas mask in the base rules. I've created a separate effect for it as more than just gas masks confer the same effect.
**Night Vision's an optional rule that's tied in with some rules I wrote for 7ZTv
*** As it would be a bitch to move your head about in such a heavy helmet. This is assuming the user's not wearing the armour, thus the lower strength requirement. It may seem like crap, but its the only way to achieve a Rad Resistance (3) – other than through using drugs, etc – with the suit.
Special EffectsPsychicalWeight CompensationA Cast Member may select this special effect if they have a strength of 5 or higher.
Cast members with this effect may equip themselves with weapons listed under the Heavy Weapons section. Due to the bulk of such weapons such cast members armed with a heavy weapon gain the “slow” effect, but ignores the Two Man Team and Move or Fire effects if it has them. * Note this is available to all cast members, not just those in power armour.
Additionally I'm intending to write up an upgrade system including things like Tesla (boost to energy weapons), Hardened (Higher Defence boost) or Advanced Servos (lessened agility negatives, or even a boost), with the Advanced types of armour allowing for a larger variety and number installed. However I'm not sure if people are really open to this added level of complexity. Personally like the additional level of depth, and it expands the roleplaying aspect of the game more, but whether that fits the theme of the base game I'm not sure.
Point: These rules aren't playtested, nor complete. =P
And, just to give tidbit for those who aren't into the rules talk, I found one of my old Imperial Guard APCs (it has a removal rear hatch that turns it into a Griffon Mortar Carrier too). It needs a repaint, but my NCR Heavy Troopers (yeah, because a strike team of them wouldn't be totally OP) or American Remnants could use it maybe.
