While I agree that looks very cool, ergonomically it would be a nightmare for thumb typing. For a thumb board it needs to be narrow enough that you can reach any key with either your right or left thumb while still supporting both sides with the web of your hand.

Hold your hands out in front of you and pretend to type. Transitions from "T" to "H" are going to suck because of the amount of shifting of your hands to reach the letters then repositioning the hand to support the other side.

I'm not trying to be negative, keep dreaming. But ergonomics and UI are not easy to get right.
David