If you picked up "Green Day: Rock Band" this week and downloaded the "21st Century Breakdown" track pack, you've seen all the songs the game has to offer. Harmonix isn't planning on releasing additional DLC for the game, since it would require individual motion capture work and animations for every song. However, Chris Foster, the project lead on the game, isn't counting out the possibility of having more Green Day tunes in the future.
"We're all hoping there's gonna be more Green Day music inside of 'Rock Band. ' This game has a level of presentation of all the songs with these fully mo-capped performances and unique visuals in the venues and unique artwork tied to the DLC that we have from '21st Century Breakdown.' We're gonna seal off the game disc around '21st Century Breakdown' and the tracks we have from the earlier albums. We're definitely looking forward to having more songs from Green Day and maybe all their side projects. There's hopefully plenty of room for that in 'Rock Band' down the road."
The initial track list of "Rock Band 3" doesn't have any mention of the band, but given the fact that the band's early work was totally untouched in "Green Day: Rock Band," there's still plenty of content to pull from.