I'm the one what got Spleen into it. Also, the GH1 and 2 tracks have been ripped and uploaded various places, you can find a torrent somewhere...GH2 have problems with with balance, though. personally, I like www.fretsonfire.net for getting new songs. Gotta sign up.
I use a mini keyboard, with holes cute out of the side. The I put some K'nex pieces in, and I attached my strap to it.