We've thought of using racing wheels for the OI, but it was all digital inputs. My sugestion is not to use any game controller, unless you can find a wiring schematic, especially if you mix up power and ground. Other things you have to do is make a connection system, decode the signal, and make a circut to control the robot. There is no way you can design one now, but offseason you can try.
I found a wiring diagram for a N64 controller
here
P.S. I don't think you can use WaveBird controllers because it may interfere with the control system. If you can figure out what the frequency is, and it is not 900 mhz, then talk to First. They will probally say no.