This sounds like "The truly superior pilot is the one that uses his superior judgement to preclude having to demonstrate his superior piloting skills".
If the Tesla was a hybrid, you might have a better chance. Or, you might be able to build a switching power supply to pull power from the main traction battery that I believe is 450V and about 40kWhr.
One of the great stories to me was that the Tesla Cars do have a 12v battery that is there to power conventional systems, and if it goes down the vehicle is disabled.
Matt
