You could use an old GC controller and start there. Use the cable to make some sort of converter so you can actually stick your amiga joystick in your Wii. Don't know if you have to do much hardware modifications to your joystick or that the signals are even the same...
Seems to me that you could use the dpad hardware and button A from the GC controller.
Look at this thread also:
Atari joystick modEdited 1 time(s). Last edit at 08/20/2010 01:40AM by DeeKay.