I think it would be massively cool if Gearhead got made into a DS and Wii game. The DS game could be like a combination of GH1 and GH2, the Wii game could be more of a MechWarrior and FPS combination. You could hold a pair of Wiimotes like throttles, maybe get a special pedal controller...
Wishful thinking.
But seriously, think about it: GearHead DS. I'd imagine it would be really cool with a touch-sreen interface. There's NethackDS, or maybe it's NethackGBA. Can't remember. There's also Powder for the GBA. I would jump out of my seat to buy GearheadDS, even if I couldn't add custom mecha. You'd really have to pad it with features, though: after all, it seems that all the "meat" of GearHead is stored in .txt files. Maybe if you got the GH1 story transplanted into GH2, with all the coolness of factions and batteries. What's also cool is that the DS really features 3D graphics, which means you could make 3D models, and you could even (possibly) see changes in things like heads and arms. The problem with that is that GearHead itself dosen't mind if you slap 8 legs on a mek. I have no idea how big DS cards are in terms of storage, but I'd imagine you could easily fit all the stuff from GH1, GH2, and the upcoming GH3: Terraformers. (Joke, of course.) There's also the problem of porting the programming bits to the DS, which is again something I can't speak on at ALL. I am, however, thinking of getting some devices that would let me get Powder and NethackDS up and running in the near future, so if you decided to try it, I could test. Maybe. No idea. It would probably help if YOU had a DS.
Just don't make it a PSP game... I'm still raw about the PSP getting Cave Story.