apparently MS is experimenting with something along these lines, but on steroids ...
I recognize that Microsoft guy in the video. Seen him before. Can't recall his name.
But he's the evil dude who runs the entire "Accessibility" division for Windows. Maybe not much of a division, really, since it's a bit of a one-man-show. He designs all the interfaces which allows Windows to be used by handicapped, blind, deaf users. (Though not the dumb users: Microsoft has other teams working on that.) So now all you people who are really happy or really pissed with the way all the Windows Accessibility features function will know what your target looks like.
Anyhow, this suggests to me that 1) this keyboard concept will hit the market, and 2) they'll spin it as some kind of accessibility aid, ie: cost will be hugely inflated for no good reason and availability will be hugely limited.