Two videos out in the wild show Guitar Hero 5 gameplay and two rockers as whom you may perform - well, in the Quicktime events anyway. Matt Bellamy of Muse, and Kurt Cobain of ... does he need further identification?
These vids were uploaded to DailyMotion by user SchnackAttack. Here is Cobain, performing, what else, "Smells Like Teen Spirit."
And here is Bellamy, performing Plug In Baby.
Expert guitar looks like a real beast, although we expected no less. Also guessing that worms-eye view of the walkdown will begin any set in which you play as a real rocker.
Guitar Hero 5: Kurt Cobain and Matt Bellamy Playable [GoNintendo, and thanks Sam B., Derek D. and Gorago V.]