If any of you guys build one, be sure to use rectagular metal & not square. 1"X2"X14 gage is real strong for just about any weight. You could get a good photo off the internet & copy one. You need the different angles though. Maybe someone would send you a brochure about one.
If you all come down pretty soon I could probably build one in my shop in one day. I have a mig welder & can get steel pretty cheap.
I've built things more complicated than that in 1 day w/the owners help.
One of you could bring casters, one could bring the cushion, one could bring the adjusters & one could bring a short steel ladder to stand on to weld the top shelf on. LOL
I also have a chop saw, a torch, bench grinder, hand held grinder, many clamps, xtra welding helmets for the curious & a willingness to screw something up w/out the proper supervisorship.
Larry