I saw mention of this on /. and thought others here could appreciate it. 

http://www.norhtec.com/products/gp/

A mini ATX form PC with no fan necessary. While I will eventually buy one for the living room DVCR function, it would be an easy grab to use in the van too. 

Features I like:
ac/dc power
10gb hd
5v @ 1.8 A
Dual screen support
USB

Though it may not replace the laptop for dvd's and GPS any time soon, it has potential. Maybe a fixed unit in the back with an additional small screen for gps by the driver? Movie server in the back? always on mp3 server? ETKA? Don't get me started on camping automation ;) 

If nothing else a linux kernel to hack around on while enjoying the great outdoors.