If anyone is still interested in picking up the game and hasn't checked their local Sam's Club in a while, I stopped by mine yesterday at random and found one PS3 and two X360 Guitar Bundles for $39.91. They also had the original game and wire for $4.91 and the Guitar and Bass game and wire version for $9.91.
Needless to say, I picked up the PS3 one for a family member yesterday and went back to get one of the 360 ones for myself (along with the PS3 version of Guitar and Bass) today. If what I'm hearing is correct, the guitar itself can be used with either system, so, really, it's the disc that is important. So I'll be able to play on both systems.
Dust is pretty thick on the boxes... and the other 360 was dented in a bit. The sticker still reads $188.98 on the box. Wonder how long they've been laying dormant. Also, they only had four of five of the PS3 games on the shelf, but around 20 more of both the 360 and PS3 were tucked away behind some boxes under the shelf.