Holy cow man are you in for a ride. Vehicle telematics, which is what we all design on this website is addicting, once you start you and your wallet just cannot stop.
The concept computer you are describbing sounds very similiar to a normal carpc that we design, and I suggest that you just do some more research on this website.
As far as the dual monitor stuff, here;s my suggestion:
Get a systemboard with an AGP slot and buy a graphics card with DVI and VGA outs, (you can convert DVI to VGA). Then install windows XP (because it has built in dual monitor support) then add all this junk to the concept pc you have in mind.. your embarking on a long journey that might cost you a fortune.. good luck