The trouble is there are a few different ways to do it. And none are close to compatible.
1st thing to find out is on the XBox (I don't know) what type of controller is it? How does it get the data to the device.
PC's usually use 100k pots (potentiometers).
Arcade sticks use 5k pots.
There are also hall effects (maginets getting closer and farther away) on some arcades and the dreamcast. But these aren't all compatible either. But the advantage of hall effect sticks is when the controller is all the way in one direction, the connection is open... so you can connect an arcade joystick to it in most cases.
If it uses a pot... then your in luck. You can find any analog controller and swap pots. Can be expensive though.
If not...
you might be able to just rearrange the controls. (if that would help).
desolder the joystick from the board... then add wires between the original board to a blank circuit board that you get from radio shack... then mount it where you need it. Or maybe even keep the backend parts.. but replace the stick... but usually you have stability issues.
btw, have you contacted Microsoft to see if they have a line of products?
One last question. Did you friend have a favorite arcade game that he could use the controls? Other then its always fun to see what arcades others like, it might help give us ideas on how you might be better to try to hack the controls into a layout that way.
good luck
