ipod joystick (xbox controller)

I was wondering if this was possible:
to use the arrow pad (like on a PC) or a xbox controller able to be pluged into the bottom of a 5g ipod so that I could play gameboy games and mabey even xbox games through the controller and mabey even plug the ipod into my TV and play 1 player xbox!
so.... is it possible (with rockbox or ipodlinux)

mabey it could work like this:
get a double sided female USB port (the one that u plug stuff into on your PC ) and put it on the end of the ipod usb cable and then take a xbox usb controller on the other side and VWALA a xbox controller for xbox
any ideas because this weekend me and my dad are going to try it and it would be extremley nice to have some advice/pointers

thanx in advance