The Rock Band developers will continue to support Rock Band 3 and are working on "some unannounced projects."
http://www.nintendoworldreport.com/news/24596
The entertainment giant Viacom sold Harmonix, the developers of Rock Band and Dance Central, to Harmonix-SBE Holdings, which is owned by Columbus Nova, an investment firm that manages more than $10 billion of assets.
Harmonix, which was bought by Viacom in 2006, will go back to being an independent developer that is privately owned. In the sale, Harmonix will retain the IP rights to Rock Band, meaning they can make new entries in the series if they choose. Additionally, the sale does not affect their relationship with EA, who distributed Rock Band 3, and Mad Catz, who make peripherals for the series.
"The DLC schedule marches on for Rock Band," said Harmonix's John Drake about the company's future. "We will continue our support of previously released titles and we're hard at work on some unannounced projects that we think you're going to be pumped about."