I heard today that The Beatles for the first time ever licensed their music to be used... for a GH Beatles version... similar to the Aerosmith one, it will feature all Beatles songs... sounds pretty cool.
It's no surprise, actually. We've already gotten Aerosmith and we should be getting Metallica from GH.
I'd actually think the Rock Band series would launch a huge song pack, and you'd be able to download the songs, but we'll see. They'll do anything to make money, but than again, what company doesn't.