first idea of my project was using a thinkpad too..
i searched a lot for using WOR (wake on ring) or start on power.. (or WOL)
-if you like to simulate a original phone-call, you need a 70V signal.. hard to built device! (for me..) or if you wanna try to wake up by simulating a external modem on COM port.. you have to switch a low/high signal on pin 1 and 2 of COM port! but this was also too hard for me..
-start on power doesn't exist for laptops..

i never seen a laptop with that bios feature!!
-simulating a WOL signal would be hard as ***!! you have to create a magic-packet with MAC address by using only a electronical device..
sure you can use a docking station and if there's a power button you can cut the cable and make a button in dash!
but i don't like this solution..
the same problem is how to start laptop with ignition?? you could use a relay that's connected to the same button..
now i wanna use a ITX mainboard fix built in behind my glove compartment!
i know..
you don't have problems with running pc without car battery and you don't have to leave laptop in car.. you have to decide! good luck..
