Wii MAME has recently been updated so that it no longer uses the SDL and has better joystick support and now the Gamecube joystick works.

It can be downloaded from here and on the ROMs I can get working it runs quite well but unfortunately it runs on the 0.134u4 and I can't find a good romset and have never been able to work out how the MAME ROM converter works.

Nemesis runs slightly faster than it should.