For some reason google is failing me...
There is a Guitar Hero/Rock Band wireless keyboard (or "keytar") made for 360, Wii, and PS3.
- Are there multiple versions of this controller, or just one?
- How do they connect to these three consoles?
There are multiple versions of the Rock Band 3 keyboard, which I hear are incompatible with each other.
Note that you can also use a standard MIDI keyboard rather than the specialized keybord using the "Rock Band 3 MIDI PRO Adapter", which is also console-specific. If you were feeling especially perverse, you could use that adapter together with the MIDI-out of a Rock Band 3 keyboard for a different console (but you'd have to use the buttons on the adapter).