From G4tv.com:
"We just got the hot word from Neversoft's Brian Bright, and we have some big Guitar Hero World Tour news:
A new peripheral is coming. The new periph. is specifically for the game's Studio mode, to help you make music, and while Bright wouldn't go into detail about what it will be, we are speculating that it will be a keyboard. Again, not for use in the game, but for use in the game's studio."