Suggestions for light rules Scifi combat?

[baldlea]

I'm thinking 20-25 models to a side. 20 troopers, 4 heavy weapons, 1 or 2 leader types.
I have 4 squads of 5 ( 4 troopers, 1 heavy)
1 Captain and a Sgt.
The other side I have not decided on models.
If that helps....

Clash on the Fringe by Nordic Weasel. Absolutely bang on the figure count and includes a system of building stats and abilities for all sorts of aliens.

[Froggy the Great]

I'm late to the party, but I'm writing FUBAR Heroes, a squad-size unit=single model variant on the platoon-size and well-tested FUBAR rules.

[eilif]

Three more late-comer suggestions.

1) WarEngine/Shock Force is back as a pay-what-you-like PDF.  I think it would definitely fit the charachter of the pulpy figs you've shown.  You can use the supplied force lists as a starting point for building your own forces with their unit creation mechanic.  It's scaled for exactly the kind of game you are asking about.  http://www.wargamevault.com/product/192892/Shock-Force-Second-Edition

2) Blasters and Bulkheads is a possibility.  Built on the Super/GoalSystem engine, it's a good system if you want to have some powerfull charachters and bands of henchmen.  It's really geared toward heroic movie-like games.  Perhaps not as good if you just want squads of dudes, but worth a look either way.

3) The new edition of Warpath that was just released has a "Firefight" game that is about platoon level.  Maybe just a top end of complexity for "Light Rules" but still more streamlined most other rules out there.  Does not have  unit creation mechanic but has a large number of army lists included.