Introducing the Fluid Piano.
It sounds more like a fortepiano; I suspect that the slider mechanism wouldn’t work well with extremely high tension strings like on a modern piano. Part of that might be intent as well; the instrument blends well with sitars, which was a concern of the inventor. But this appears to be the first microtonal piano with potential, as it does not involve an unfamiliar and complex keyboard and is easily user tunable in real time. Of course, tuning during performance requires use of one of the hands.
I suspect that it’s too little, too late, given the existence of cheaper, more portable and more versatile virtual-piano products. But it’s a great idea.