Just thought you might be interested in the XBox 360 Arcade Controller I built recently. It uses a painted original XBox 360 case, wired controller, arcade parts and a few other assortments. All of the buttons on the 360 controller are used and the analog thumb sticks have also been retained. Some of the more unusual and interesting features include LED rumble, functional front USB ports (USB 2.0 hub soldered inside) and the original power button re purposed as the XBox guide button.
A full overview is available at http://x2jiggy.com/post/8339834991/xbox-360-arcade-controller-overview