Fuel Cut off Switch, here ya go

Hmm, not so sure about those switches in plain view OneDopeTeg. If this thief is as good as you said, having scouted the car. Although he's almost certainly not going to spend the time going through every combination, he may try the ol' rip the switches out and connect the wires by hand trick. Most thieves don't concern themselves with messing up the interior a little. So yeah, go with a nice alarm and a kill switch that's not hard to reach but is not in a very visible area. Then you can be fairly confident your car is safe.

Though, I do like the big dog idea. Have to feed it and like, make sure it's "car trained". Seems like too much maintanence. Maybe an attack android that sits in the back seat could deter thieves...