Alright, so I know Mecha RPs are a dime a dozen, but I had an interesting idea;
What if every single player is the same person, just different facets of his/her personality, mentality, etc, each differing by focusing on different part of said fellow and in appearance, split by some sort of military experiment and the "personas" sent to fight in a war, fighting using mechs? Possibly against more of their "kind", people split in the same way? Or aliens, sort of like Angels from Evangelion? So, what I'd probably do is give a basic character to base off of, or maybe choose a character out of player's ideas, and then players would make up their own "persona" based off of this guy. This would make for quite an interesting RP, IMHO, and could explore various psychological concepts, and not only that, could also take a look at how a "person" is affected by loss, even more by loss of "himself"?
Please give your thoughts, and tell me if I should pursue this idea!