Personal Car Communicator
Check this out. It's a option on the new Volvo S80. it's not cheap at $495 but it's damm cool!
Personal Car Communicator (PCC), including keyless drive, two-way remote communication of vehicle's security status, and heartbeat sensor
The Personal Car Communicator (PCC) is your car key's smart connection with your Volvo S80 applying the latest in two-way radio technology. When in range, you'll always know the status of your car. Locked or unlocked. Alarm activated or not. If the alarm has been activated, the heart beat sensor will also tell you if there is someone inside the car. The PCC also includes keyless entry and keyless drive.