The team at Magic Lantern have successfully managed to make Linux run on a Canon SLR camera. So far, it has been successfully tested to work on EOS 60D, 600D, 7D, 5D Mark II, and 5D Mark III. Previously, Magic Lantern had piggy-backed their software on top of the existing Canon firmware. This discovery means that features can now be implemented cleanly and addressed directly to the camera’s hardware.
Magic Lantern are looking for people to develop the software. The binary and source code can be downloaded for people to tinker with.