Go with Xarcade's control system, works for mame and dreamcast + XBOX + PS2/1 + GC with adaptors. I am not sure (probably not) that the 360's will work as they require USB input, but any traditional 4/8 way sticks (mag stick/happ ultimate, etc) that wire to arrows will work.
I am interested in if I can hack apart a saturn controller and attach it to my controls directly along with the Xarcade system (so I can play virtua fighter et al)...