@Huezo,
The XBox controller is basically a USB hub and this uses a different method than direct pin asignments like a cd32 pad.
heres some more detail on the xbox controller
http://euc.jp/periphs/xbox-controller.en.html
arguably you could convert the cd32 controller into using this
http://eab.abime.net/showthread.php?t=31515
(i may redesign this design *again& and make it 2 layer non drilled)
but it would require a little experimentation with some of the code to get all the features of the cd32 joypad.