Since its release at the tail end of 2007, MTV Games and Harmonix’s Rock Band has already redefined the music and rhythm-based videogame genre, building substantially on the foundations initially laid by the groundbreaking Guitar Hero series. Now, with Rock Band’s popularity seemingly assured, promised downloadable content could see as many as 200 new tracks released in 2008.

According to a related report published this week by IGN, more than two and a half million longevity-giving Rock Band song tracks have already been downloaded via the Xbox Live Marketplace and the PlayStation Network and the game’s creators are keen to maintain the delivery of weekly content.

“The thinking at the initial launch was to supply a deeper dive into three key artists already on the disc - Queens of the Stone Age, The Police, and Metallica. But then also supply songs that provide tremendous gameplay experience that we couldn’t quite get on the disc.” commented Paul DeGooyer, Senior VP of MTV Games regarding the projected focus of Rock Band’s extra content. “That’s kind of what we’re clearing out now. I think you’ll see, if not concentrations of genres, perhaps expansion into other sub-genres of rock. And perhaps a bit more of an apparent organizing principle to what is being released.”

And, while ongoing recognizable mainstream tracks from prominent bands will remain available via Xbox Live and PSN, DeGooyer offered that music fans hoping for access to more obscure content would not be left out in the cold. Citing the game’s impressive early success – of a level the company was not expecting – DeGooyer explained that a great deal of confidence had prompted a move forward to satisfy those looking for more selective track listings.

“The whole goal is to get the music that resonates with people…” outlines DeGooyer, “That’s exactly what we’re trying to do… We want [Rock Band] to be a platform where all levels and types of music can hang off of it.”

Furthermore, IGN suggests that current track releases, which have typically arrived as trio packs, will occasionally be punctuated with weeks that see MTV and Harmonix delivering much more downloadable content to fans. And that includes those promised full album downloads that were touted way back in Rock Band’s development.

Apparently, full album downloads are only being delayed due to technicalities relating to delivery issues, DeGooyer clearly states that content deals and partner support regarding full albums was “done and dusted” a long time ago. Interestingly, the MTV exec also added that more videogame-related music would become available via download for Rock Band in the future.