Just need to work how to build the first one ;-)
That 2nd one is almost feasible. The body part of the instrument itself could work. They have the skeletal elements and hinge points figured out for the playing arms. But rigging them with actuators that would be small enough, strong enough, fast enough, accurate enough, yet still quiet enough to play it without burying it in miles of hydraulic lines or wires and losing the beauty of it would be a real trick if anyone were going to try to build it outside a computer, and the only thing unrealistic about it.