According to this post on IGN, it seems that Aerosmith won’t be the only band to have its own Guitar Hero game.

It was uncovered in a report filed with the Securities and Exchange Commision, that Activision made mention of a new title, Guitar Hero; Metallica. Since the game is mentioned in the fiscal reports for 2009, it should be available in stores before that time. Although the details on the game are scarce for now, with this information leaked out to the public, you can be sure Activision will have more to say on the game in the very near future.