Pianoarc is a circular keyboard developed as a dramatic stage presence for Lady GaGa’s keyboard player. It’s really customized to his particular reach, and it comes on a stand that can be tilted up to 50 degrees for visual impact. The thing has 292 keys, including 3 full 88-key MIDI controllers, plus a smaller section used for program control. They got some top engineers from QRS to make the electronics, and the keys were cut by a Steinway tech. The keys are wood, but are sprung (not weighted, obviously, due to the tilt stand). The action uses special optical sensing in some way that I’m not that clear about. The thing is a prototype shown at a recent NAMM show, but they are soliciting orders for custom versions, “about the price of a high quality acoustic grand piano.”
What is interesting is not so much the circle, but the arc. Ergonomically it makes sense to pivot the arms rather than to lean in and open up the shoulders as when playing a straight keyboard.