Got GH2 recently (it was on sale) and i started playing again and it had better 2 player functionality and I didnt want to play for a new one, so I got a whole heap of crap together.
Body: A gutted PlayStation
Neck: Off cut from my DDR pad
Strummer: Arcade joystick from my machine
Buttons: Regular buttons, there red and square.
Internals (In video there different): PS1 controller from ebay

Taken after the video was taken, original internals were a old PS1 dance mat controller.
Video:
http://youtube.com/watch?v=AOOEW1hdw5I
Video has some annotations that go into more depth (i think)
