If you need more inspiration for WSYW then check out a few of the sites on;
http://emperor-elector.blogspot.com/it's mostly straight C18th "imaginations" but with the odd flight of what would be considered sci-fi in the C18th.
I'd love to do an army backed by "leonardo's machines" - flyers and "tanks" etc.
The other advantage with this period is that the troops are so colourfull not that dull "mud" colour of the C20th.
I'm with Gluteus Maximus on the Grenzer idea, "Von Tegale's Dampfgrenzer Huzzaren" mounted in armoured steam wagons!
- not sure that german is correct!
The Hooded Claw - One idea for the base figures for your superhero games could be either the foundry C18th civilians range or the Perry's Carlist war range. If you're after a more military look then how about the plastics from Victrix, they have some early Nap french coiming up.
vT