On the wear-hard mailing list, Doug Sutherland tells us about some interesting keyboards:

Maltron 3D One Handed Keyboard http://www.keytools.com/keyboards/maltron3dhand.htm

Maltron 3D One Finger Keyboard http://www.keytools.com/keyboards/maltron3dfinger.htm

CyKey Chording Keyboard http://www.keytools.com/keyboards/cykey.htm

LUCY Hands Free http://www.keytools.com/keyboards/lucy.htm