For the past few years I've been building my laptop system that I use in my 18-wheeler for driving OTR. It's taken a bit of "fiddling" between different things to get exactly what I want, and I'm just about there.
Basically, I have my laptop mounted in my sleeper. There is a 7" touchscreen monitor mounted to my sunvisor in the cab, along with a small USB keyboard w/touchpad. I mainly run ALK's CoPilot Truck Laptop 9.
If you'd like to check out the system, here's a link:
http://www.freewebs.com/malaki86/mycurrentsystem.htm
If anyone has any comments, questions, etc, let me know. I'll be more than happy to answer them.