I took a look at this a few months ago, but now I'm starting to get really interested by it. Matias has created (and is now shipping) a one-handed keyboard. Unlike chording or fitaly keyboards, this one is based on qwerty, but includes the left hand keys only. To access right-hand keys, you hold down the space bar and press the corresponding mirrored left hand key.

Don't take my word for it. They have demo software for both Mac and PC (links at the bottom of the page) so you can try it with your existing computer and keyboard. It's surprising how easy it is to get used to it. I type 65-70 wpm with both hands, and while I can't hope to get that fast with a single hand, I'm already at about 15-20 wpm after playing with the thing for 5 minutes.

I'm a lefty, and it probably favors lefties, but it's worth checking out anyhow. What's more, they offer the keyboards for Mac, PC, and most varieties of Palm including the Visor.

This is definitely something I'm going to take a look at when I go to MWSF next week. I have plenty of desk space, but I might want one of these just so I can keep one hand on the mouse and the other at the keyboard.