... found this perfect tablet PC from Nokia, at the right price point.

http://linuxdevices.com/news/NS5409534614.html

ARM core

$359 for 800x480 touch-screen, MMC, but the USB stack seems to be in device mode so might make interfacing USB components like OBD-II reader a little tricky.

EDIT: looks like it can also work in host mode, but cannot power attached devices (obviously), so it's no biggie to rig up external power.

_________________
DIRTY KJ :: flickr photostream
"Primitive life is very common and intelligent life is fairly rare ... some would say it has yet to occur on Earth" --- Stephen Hawking