I have a very old mini-itx board and a 60W power supply that looks like the PW-200V from http://www.mini-box.com/DC-DC
I used it in the early 2000's for an in car mp3 computer but have it setup a simple NAS device now. Plan now is to build something like an online UPS using a battery and solar charge controller with the low voltage dropout setup to switch to line power rather than disconnecting the load. Then run my server, wireless, etc all from 12v.