I've also recently ordered a Z1 unit, and should have mine by the end of the week.
I'm considering adding a carputer as well, but I won't attempt anything until I break the unit in for a month or two. (Just in case anything goes bad, I'd want warranty service before I void it..) In the pictures posted on this site, I didn't notice any standard connectors that would deliver the touch-screen coordinates to external devices -- unless there's some kind of bus adapter like the one used for the Mac Mini in a Toyota Prius hack.
So, I'm preparing my lab for some warranty-voiding and mad soldering -- hook the Z1 up to the bench, identify the touch-screen controller chip, and see if I can find any useful signals that could be routed out to an external circuit.
I'm also working on a few ideas to sniff the IDE bus to grab the ATA Passwords used by the Z1; or (at the worst case) build a "hot-swap" board that can be inserted into the Z1 (basically a long board or ribbon-cable with a 44-pin, 2mm connector on the end), with something to hold the notebook drive, and a standard 40-pin connector for a PC.
The worst-case design would at least allow the notebook drive to be powered (by an external power supply), temporarily connect to the Z1 for unlocking; and then move the (still powered, and now unlocked) drive to a standard PC for file manipulation.
Anyways (I'm rambling, sorry...) If you find something that exposes the touch-screen coordinates before I start on this project, though, I'd be interested in following your progress.