Metal Fatigue from 2000 is an RTS where, as well as usual units, you can build mecha/robot units out of parts, can even scavenge and re-use parts as i recall. there are 3 levels of combat - orbit, surface and underground

i found it enjoyable but as difficulty increased almost impossible to keep up across all three levels while also trying to optimise use of the robots!

the story wasn't one that stayed in my mind though, the usual alien threat type i think. The c&c series win on story in the rts genre imo

Honestly can't say if the story was good or not, as I never really played it myself, but back as a teen, I had a friend that really loved War Breeds. I remember him showing it to me and it seemed very different from the more well known games..

Does anybody like Serf City (Settlers) ? Not much of a story, and Im not even sure if it is a real RTS, but just watching these guys chopping wood or baking bread was soo relaxing...