The TechCrunch crew tested an eye tracking software (a tracking system for your gaze) that has been retrofitted to work with WoW. Basically the cursor goes where you look on the monitor and looking offscreen in several directions will trigger different modes (i.e locomotion, combat, loot).
Eye-gaze systems bounce infrared light from LEDs at the bottom of a computer monitor and track a person’s eye movements using stereo infrared cameras. This setup can calculate where on a screen the user is looking with an accuracy of about 5 mm.
This "Snap Clutch" software has been developed at De Montfort University, UK in collaboration with University of Tampere, Finland. The idea behind this project is to help the handicapped (or not), you can do some things as solo/group pve in WoW, but you would have serious troubles in pvp & raids without a keyboard.