My friends developed something like this, not near a finished product, but a prototype for our final engineering capstone project. They took 2 touch screen lcd screens and had it so a display of keys in a full keyboard came up, of course in the MS natural keyboard layout, 1 lcd per side. Worked pretty well, response time was reasonably fast, and could translate to multiple languages, usb interface. Just kinda weird to use at first, kinda like tapping a table top. Still cool tho. And not very practically priced..
either way the first keyboard is fkin awesome.