I have a project that uses Teensy USB board which you may want to add to the projects page.
Here is a link with full source code: http://github.com/grunskis/gamepad
This may go as a description of my project: "This project is my first attempt in creating USB powered arcade game controller. Its going to use Seimitsu LS-40 joystick & two Sanwa push-buttons."
I've attached few photos.