for header-sized items and smaller...why couldn't someone bisect a 55gal drum, like they do for grills?
the floor is already perfectly shaped for media collection, then a hole at the bottom that feeds back into a cheap sandblaster unit like the one from sears;
http://www.sears.com/shc/s/p_10153_12605_00916706000P
(by the way, the essential parts can be had individually for less)
a cheap droplight hanging from the lid, and some plexi for a window, and you're done. best of all, just like a grill, it can be made on a cart for portability.
if you really wanted to go hollywood, you could insert a 2ft section of straight sheetmetal between the halfs, and it would be 4ft tall.
i've seen it, and it works.
