Albert suggested I call this project Fido. LGTM.
I made a lot of progress on Fido this weekend. It now has an Arduino on board to control all sorts of fun things. Most importantly, it controls a working headlight (a fancy 100 lumen LED flashlight) and a relay to cut power between the OLPC and the Create. I made a custom end cap for the flashlight out of a PVC cap and some flexible black tubing that fits snuggly over the light so that I could hook it up to a transistor switch.
I also committed many enhancements to PyRobot to support logging on the web UI, soft resets, and some bug fixes and error handling that improve robustness.
For pictures, have a look at my Picasa Web album.