There's Unlikely To Be Anymore Rock Band Unplugged DLC. But There's Still Tons To Choose From.

For the time-being anyway. The company told Joystiq that Rock Band Unplugged has "run through [its] planned slate" and that they were "very pleased with the performance of the Rock Band Unplugged game on PSP, the Rock Band PSP bundle and PSPgo starter kit".

Harmonix didn't rule out future releases, but did state that the team are now busy working on the "Rock Band Network, weekly console DLC, and unannounced future projects".