Dominions 3000 (name confirmed!)

[Endoperez]

From mechanical standpoint, what about making MA Ulm, in space!, that actually works?

Very cheap basic units and ships with high resource cost. Low base stats. Very good special abilities (protection, magic resistance, magitech can help in important resistance and encumberance problems). Elite units are very expensive but have good stats/weapons in addition to sharing the abilities of base units.

Could be base human race, or telekinetic space pineapples in mechanical bodies, or something else.

[llamabeast]

I strongly suggest starting with just 2 races, or even just 1. That can be the prototype, which gets all the basic ideas worked out. (You can have two copies of that race, so that test games would be possible.)

A good one to start with might be Humans/Terrans. You know, marines, maybe some mechs/tanks, and reasonably non-weird spaceships.