Besides the USB interfaces for the x-box are non-standard so it juse becomes more and more of a hassle to add stuff to it.
The x-box has one extra wire, but other than that its a bog standard usb port which you can rewire to a standard usb socket.
Interesting that they ported WinUAE though considering that the Windows OS isn't in the X-Box.
The x-box runs on a moddified Win 2k os with directx 8.
The hardest part of getting this port to work is getting the xdk to compile it.