Ben,
I have watched all your pod casts, and while researching another topic, I though of you. There has been growing interest in simple ROV designs, that can be built mainly from local DYI center components ie PVC pipes, etc. Some of the challenges are the motor design, control system, camera, etc. I have seen several that use induction motors, with RC speed controllers, usually oil filled, etc. It would be cool to see your spin on this project!!!