Not able to check out the video as I'm at work, but that looks like a pretty cool setup judging by your parts list. I've got one in my Ford Contour as well. Got the idea from my friend who put one in his car. I've got a mini-ITX board which with an integrated VIA processor that I thought was small, 6.7inches x 6.7inches. But 3.5inches? Holy moly! The mini-ITX board I used just barely fit behind the glovebox mounted where the factory stereo amp used to be. It's tight back there with the laptop hard disk and the power supply/shutdown controller. For a monitor I've got a 7inch LinITX screen and I haven't mounted it yet, it's just flopping around loose which is kind of annoying but after getting it all working I got lazy with trying to fabricate a way to mount it. I'm running XP on mine too and boot up time isn't bad. Takes about a minute or two. As far standby goes, I don't think I'd configure it that way. They suck a fair amount of juice when in standby and if your controller board does not have a low voltage shut down feature you'll kill your battery.
I have this problem with my lcd. I power it from the 12 volt cig lighter and when the car pc turns off, it goes to standby. For some odd reason Ford has their cigarette lighter wired to the battery as opposed to the 12 volt accessory. So I figured, it's in standby it should barely be drawing any power. Doesn't even have an led that's lit. Boy was I wrong. Left my car for a week at the airport parking garage and the sucker drained my battery. Now I make sure to unplug the cig lighter plug every time I leave the car. Anyway's just a heads up on some of the issues I ran into with it. Other than that, it works great. Wired right to the aux in of my Pioneer deck so I didn't have to screw around with an amp for the speakers.