I wonder if the XBOX 360 USB controller would work in MorphOS, of if special drivers would need to be written.
No, the XBox360 wireless/usb controller will not work because it's not a standard joypad device (hello, it's m$ we're talking about, they always have their own substandards

. I am however working on a driver, so it might work at some point - depends on my amount of free time / motivation to mess with usb though, so I cannot really promise anything.