Early version of a GDC presentation points to a 2009 release date.

lego logo - Harmonix designer reveals LEGO Rock Band

An early version of Harmonix senior designer Dan Teasdale's GDC session, "Dirty Deeds Done Dirt Cheap: Design Lessons Learned From Rock Band," has been published, revealing a LEGO Rock Band game.

While all talk of LEGO was stripped from the actual GDC session, a release roadmap slide from an earlier version which was sent for approval shows the game for release in 2009, between Rock Band Unplugged and The Beatles: Rock Band.

A later slide featured a placeholder image for a new project "to be announced before or at 9 AM Friday". So it appears that for whatever reason, the LEGO Rock Band game announcement was pulled.

Via Kotaku