I kid you not, Xenarc makes a computer that fits in your dashboard. 266MHz Pentium with 128M RAM, 15G disk, USB, PCMCIA slots and more. Although, if you look at the bottom of the page it says
“This product has been temporarily discontinued. We are currently working on a version with faster processor speed, possibly Pentium 3 based platform so that it would support Windows XP. Please check back with us in a couple of months for more information. Mean while, please take a look at our new Pentium 3 based MP-SC1 12V DC Carputer.”