i was thinking about this too....but instead of having a key and a button, setting it up like the new lexus'....there's no key just a key fob and when you get in the car, the car senses that the fob is somewhere inside, then you have to push the brake and push the start button to start the car. it'd be hard to set up....but would definitely be a nice touch. also, on those cars all you have to do is walk up to the door, not touching anything or any buttons, and it senses the fob and unlocks the door for you. they're pretty nice.
__________________
|