I've been wanting to try an idea out I've had for a while... if the alarm is armed, and the door, hood or trunk is opened, (not just the alarm triggered, but something opened) maybe have a fuse going to a wire on the ecu, something small, say 5 amps, wired through a relay, so that once a door is opened you send current to that fuse to pop it, but it would have to be wired with diodes, so that you don't send the power into the ECU. so once that fuse has been poped the car can't start... and you hide that relay and fuse obviously...

just a thought, The Saint