I think it's better to directly emulate a sixaxis or 360 pad through a teensy instead of using a third-party adapter that will limit the controller abilities.
And this adapter is not firmware upgradable (Sony or Microsoft may find a way to block this non-genuine controller).
Last evening I have started working on issue 99. I managed to emulate a true sixaxis over usb

I will do the same with the 360, and bypass the controller authentication using a genuine 360 controller wired to the PC...