A new entry in possibilities - the "fit-PC2i".

Take a look at http://www.engadget.com/2009/12/03/compulabs-fit-pc2i-is-extra-tiny-ready-for-windows-7/ for a review of the new fit-PC. It draws 8 Watt!!!!

The thing only measures 4- x 4.5- x 1.05-inches and weighing only 13 ounces. IF you are into building in a PC, it's so small, it could be put almost any place aboard!

And oh yes, you can get it with other operating systems.

Greg