Hey, one of my big interests is very small PC's. I checked around for Cubid 2677R cases and found some interesting stuff on...
They even have detailed good pictures of the stuff they sell, definitely an above-par website. Since they carry the cases you want they may be able to get the PSU. If it's a replacement part for one of those cases I understand why you're looking for one of them, but I bet you'll end up paying big $$$ for the part - if they can get one. If you're after mobile 12v sourced PSU's there are probably much better options available for similar buckage to what laying hands on that specific one would cost. And it really looks like a very low quality job (well at least low cost and simple). It might be lacking sufficient line regulation and have troubles with automotive 15v+power spikes=12v type input, since it's probably only designed to use a flat, well regulated external 12v switcher. It probably doesn't regulate the +12v at all (that would up the $), so you would have to ask if the other components could handle that without trauma.
I haven't really looked around yet, but as of miniITX and Via C3's, I can see the option of running something like it for our survey company on the sounding boat. So far we have just used inverters, at around $50 a pop in Canadaian Tire they are the other viable alternative.