Bili Inc. offers the Foot Mouse also known as the Slipper Mouse. The Foot Mouse lets you keep your hands on the keyboard and your feet move the mouse pointer and click the buttons.

The Foot Mouse is also for those who suffer from the 'Mouse Arm'. I assume it is not that easy to move a cursor accurately with the mouse slipper, but I think it is a valid choice to consider. There are many ergonomic mice out there like the vertical mouse or the 3M mouse. This one goes straight for your feet and lets your hands rest.
The slipper and the button pad sell together for $199.
To order visit the Bili Inc. site.