Matias jumped the first hurdle on earning consumer acceptance of their Half Keyboard. The Half Keyboard x2 contains two half-keyboards (I hear they spent weeks on the name), each containing the other hand's keys in mirror image. Type in normal mode all you want, then hit a button over to the right once or twice to switch to the left or right hands only. When you're on one half, holding the spacebar brings up the other half's letters. Those of us who like to optimize keyboard-mouse combinations for our crazy multisurfing will appreciate the flexibility of switching back to a full keyboard for a tricky ctrl+alt+option+P maneuver.
It takes a while to learn, but if you can learn to tap at 9-key screens until pimple-sized blisters form on our fingertips, the Half Keyboard is comparably quick to learn. Leave whichever hand you choose free for those mysterious "other things."
The Half Keyboard x2 will sell for $49.99, half the price of the half-sized board. It doesn't ship until April, but it looks a lot like the $595 Half-Qwerty.