It can run dc-dc, for instance, I use a CPU psu for it. You need 3 voltages, -8v, 12v (for the backlight inverter) and 5v.
200mhz, 20gb hotswapable drive, 128mb, Winamp w/full-screen vizes, (upgrading to WinAmp3 in near future), 5" LCD screen, controled by numberpad, Sproggy PS under construction, custom mounting case under construction.
The $99 eio LCD screen or
the $99 i-opener computer
If you mean the $99 LCD from EIO then Slicer can sell you a pre made power supply for it.
Or if you mean the i-opener, reports are that it can operate directly from the car 12V system with the engine running but it will not operate or reset with the engine off and during starting of the engine. I am currently working on a DC-DC for the i-opener that will allow it to operate at all conditions and this should be a available soon completed at $30.