Photography Bay has found a patent application that shows a tilt-shift adaptor that would work with all of Canon's EF lenses.
From Photography Bay:
First off, the Canon Tilt-Shift Adapter has its own CPU inside and no optics. But it works hand-in-hand with the Canon EOS body and EF lenses to not only serve as a pass-through for communication but to also take on some processing burdens to make tilt-shift work on different cameras and lenses. Additionally, there are motorized drivers inside of the adapter that can drive the shift and tilt axes using controls on the camera (or the adapter itself). Read the full breakdown of the patent
This would be one highly sought after adaptor if it ever gets made and works like we'd want it to.