Existe um programa blueproximity
(veja também is )
BlueProximity is a clever program by Lars Friedrichs that sets up your computer to lock itself when your phone is out of bluetooth range, and unlock itself when it comes close enought again. You can also also make it turn off and on the monitor, music, change msn status and pretty much everything you can imagine.
Talvez não seja a resposta de 100% da sua pergunta, mas pode resolver o seu problema.