Okay, okay... so it's not really a draw down indicator but it is kinda cool...

Personal Car Communicator with a heartbeat sensor - Personal security is one of the cornerstones of the Volvo brand image. Launched also with the all new S80, the Personal Car Communicator (PCC), an advanced, pocket-sized control function is like a normal remote control but can do much more than activate locks and alarms. By simply pressing a button the car owner can within a few seconds acquire information about:
- whether the car is locked or unlocked,
- whether the alarm is activated or not,
- whether the alarm is activated and if there is someone in the car, which is registered using a highly sensitive heartbeat sensor and an advanced calculation process.

The information is accessible and relevant as long as the distance between the PCC and the car is within approximately 100 metres. However, the most recent information is stored so that at any time and in any place a check can be made to see if the car was actually locked when it was parked.

(from Here)
-Mrs.Monk

I saw the TV commercial about this and it was kinda scary. Woman was walking up to the car in a dark empty parking lot. As she gets close her and her key chian started flashing she stops and runs back to the building.

Yeah I saw this commercial.  WAY cool.  I didn't know how it worked though.

And there's another one with red warning lights above the dash if you're closing on an object in the fog when you can't see it.  It's like the thing has FLIRR!