We first heard about the Rock Band 3 MIDI Pro Adapter by Mad Catz back in June of this year, and now it's finally here . With it, you can hook up just about any real MIDI keyboard or MIDI drum set while playing Rock Band 3, plus it works in conjunction with the upcoming Rock Band 3 Squier by Fender Stratocaster Guitar and Controller, Mad Catz says.
The MIDI Pro plugs right in your console's USB port and then works as an interface between the console and MIDI instrument. There's a velocity sensitivity adjustment for MIDI drums so cross-talk doesn't become an issue, as well as a full D-pad and standard gaming buttons right on the adapter itself.
The adapter is shipping now for the PlayStation 3 and and Wii, while the Xbox 360 version "is expected to ship imminently to Best Buy." It goes for $40.