A half a keyboard from Matias Corporation.
Similar keyboards roughly half the size of standard DvorakKeyboard include:
The "twiddler" and other keyers
The "bluetooth flute".
The Global Keyboard Optimised for Small Wireless Devices
I remember seeing a kernel hack for Linux that would allow you to use your keyboard as a one-handed keyboard, where holding down the space bar would allow you to type keys as if with the other hand. Since the mapping is symmetrical, the author claimed that touch typists could learn this system quite easily. He said that it mimics some of the new proposed keyboard designs for palmtops, but not being familiar with palmtops I wouldn't know. Does anyone have any more information on this? --NickBensema
Yes, see HalfQwerty.
(Should I merge the HalfQwerty page into HalfKeyboard ?)