They've had that for awhile. I think there was a problem with it needing AC power to turn on? There was a thread about it long time ago.
Anyone tried this one 57W unit yet ? Only $29 at http://www.timeline-inc.com/arrival.html
Here are the previous threads:
Help with AC/DC-DC powersupply from Timeline
Small DC-DC supply @ timeline.
Cheap DC-DC PSU - Be quick!
What happens is when the PSU turns off you need to apply AC in order to get it to power on again. There were many speculations on how to trick it into loading anyway, but nobody ever got anything to work.
If anyone does manage to get something to work though, I think that we'd all be interested in finding out more.
IN DEVELOPMENT -- '96 Mustang, lilliput with PII/450 laptop, custom DC-DC power supply, 60GB; Garmin GPS; 802.11g; compact keyboard, small graphical LCDs, OBDII.