There have been a whole bunch of them, and most of them fail because they spend so much effort on getting the box and the screen running with low-no latency that the actual control surface is usually an afterthought. Touchscreens are absolute ass for performance but most engineers don't appreciate that you need some sort of note input, at least 16 buttons to function as a sequencer, and at least rotary encoders, and they have to be good encoders because musicians get carried away when they're jamming.