Cookie is spot on-
Netbooks are fine but try driving with one.... clams are clams hence a better (IMHO) approach is this especially if you intend setting it up in a car.
(btw, the tablet works fine in the map sleeve of my tank bag too!)
Touch screen tablet with Windows 7 Ultimate (1.6 Ghz, 2 GB RAM, 50GB hard drive and a secondary built in 320GB hard drive so plenty of room in there.
3 USB2 slots, 1 HDMI, 2 SD card slots and a SIM card slot-
I'm running Mapsource, Basecamp and NRoute- and my Montana GPS send the gps signal to it-
The Montana maintains its navigation independence as does the tablet- So you can have have the two devices routing independently, using different settings and different mapping data at the same time.
With the kind help from RAM Man, I found the right mix of RAM bits to set it all up in the 4x4.
Sumprat here recommend the bluetooth Rii touchpad which should do nicely on the arm rest.
Montana 4" screen = very good

Tablet 10" screen = Awesome doesn't quite convey the 'wow' and fab display!

Check fleabay! Complete set up including mount & bits £172