I've got one that came out of military surplus. I checked and there are none listed now, but that can change every week.  Like everything you get there, I had to do some repairs, but it is without question worth having one in the shop.  Once you get one you find lots of places to use it.  It is especially nice when you are welding something that has rust on it; a clean metal welds much nicer.  Here's a link to a company that sells both cabinets and the supplies to make your own.  They show plans for a plywood cabinet, but I personally would want to make it out of metal.  Like most shop tools, bigger is better.  You can work on small items in a big cabinet, but not the other way around.