In this project I created a touchscreen car PC from an old Gateway netbook I had (the same one from
this teardown post). The specs are about just right for what I need for a in car computer: 1.66ghz Atom N450, 1GB ram, GMA 3150 and a 10in 1024x600 display. All it has to do is run XBMC or some media player for listening to music and deal with a few peripherals such as a touch screen, media keys and possibly an OBD II bluetooth reader.
Running some XBMC, but still needs a bit of cleaning up.