Hey guys thanks for the great comments. The whole thing is pretty simple, I might change the power supply to a DC-DC but for now I'm using a lowcost/lowpower inverter and it works perfectly!
At any rate here's the hardware...
Laptop: HP nc6230 from a friend for $200
Inverter: Xantrex From bestbuy $50
http://www.amazon.com/Xantrex-Techno...7538858&sr=1-6
TouchScreen: Lilliput 7" $190 Ebay
http://cgi.ebay.com/Lilliput-7-EBY70...QQcmdZViewItem
Keyboard: New Apple Keyboard $70 Frys
250GB Laptop Drive with Ext Enclosure: $130 Frys
The install was pretty straight forward. I could have gotten an Orbital faceplate that would convert my stereo to a double din, but I wanted the Grouppe-S for my prosport gauges and wanted to keep the stock deck. I decided to take out the stock clock on the dash and figure out how to mount the monitor. Fortunately the stock hardware worked perfectly I just needed a longer screw (pics soon).
To fix it to the correct angle I used rubber vacuum hose (yeah it sounds ghetto but it actually works quite well) and I'll have pics to show what I mean. I ran the cables down the center console to the laptop which is mounted via velcro under the passenger seat so I can take it out when I want. I then mounted my GPS receiver (USB) inside the center brake light and ran the USB cable under the rear seats to the laptop. The laptop is always plugged into the ODBII port for scanning and works quite well.
Oh also for remote power switch, I had to take the laptop apart and figure out the wiring for the power button, was harder than it sounds. But I spliced into that and added an additional jack to the laptop that plugs into the power switch in my ashtray (pics). This way I can manually start up the PC when I want, if I turn my car off and it's on battery for 10 minutes it auto hibernates.
The OS I'm running is TinyXP, bootup is almost instant especially when out of hibernation. MS Street Trips 2008 is installed, Trillian, Winamp, EcuFlash, EvoScan and my scanning software I've started. I'm starting to copy over my music but right now I *only* have 4000 songs on there, I have about another 200GB to put on it.
Internet is via my HTC Tilt (bluetooth) and it's fast enough here in Dallas for me to listen to internet radio at 128bitrates, for instance I can listen to 89.3 the current while driving to work. I've even tried youtube (obviously while not driving) and it's fast enough to consider it enjoyable.
Total install time (with laptop switch) was probably about 8 hours, not too bad I think.