Like shotgunefx, I am using an auto/air DC-DC power supply on a laptop. FYI, it's a Dell laptop. My laptop had an internal modem, and using an idea from a fellow forum member (my apology - I don't remember who to credit), I wired the laptop's power button to the modem plug. Then I ran a regular phone line to a momentary switch on my dash. That way I can power up/down from the switch. Also, with the proper BIOS/Windows settings I go into/out of hibernation with just a quick push of the button, and if I forget, the laptop hibernates after 3 minutes via the power settings in Windows. I didn't go the dock route as my car doesn't have room for one (no trunk, no back seat, etc.), but the dock wiring would certainly be easier to hack than soldering direct to the laptop MB.