About all you'll probably find on it will be here..
http://forums.xbox-scene.com/index.php?showtopic=652308
AFAIK I'm the only person that's made that particular controller up and the details of it are such a mess that I don't plan to make up a full tutorial on it. It'll have to be done with a Wired CL version 360 controller and an older version Six-Axis board and DS3 shell (if ya want Rumble) or use the DS3 board, but doing it that way you'll have to swap out the sticks since it uses a different type, which may or may not fly as they're a slightly different size, haven't tried it yet. The older Six-Axis boards have the 10k POT type, they're just smaller is all, but they don't fit right into the DS3 shell if ya want Rumble or ya can use a later version Six-Axis and a DS3 shell with swapped POTs, again haven't tried that combination. That's not including the larger mess if ya want to try and keep the Triggers analog (v2 in that thread) then you'll need to sacrifice 2 of the older version controller so ya have 2 daughter boards and connectors. It's quite the challenge to just build it, let alone get into the headset connector, Rumble motors and Triggers, much more difficult to make than a PS360 controller is, good luck on it.