I'm currently in the process of making an arcade style stick for my 360, seeing as how the only option right now is the DOA4 stick, which goes for well over $100 on eBay.
I've got the circuit board I'll be using (a wireless controller I spiked one too many times after some frustrating GoW games) and an old redoctane arcade stick I'll be using for parts, replacing the crappy stick with a nice Sanwa one, though.
I've found writeups for people making custom arcade sticks out of wired controllers, never a wireless one though. Shouldn't be too hard, just got to figure out how to make the battery pack easily accessible. Guessing there will be a lot of hot glue to counteract the effects of gravity.