Here's an idea that I just gave a try tonight. At Home Depot I picked up a piece of 3/4" conduit, some PVC tube and fittings that would just let the conduit slide through and rotate, a couple of small "U" bolts with matching wing nuts, and a couple of hitch pins. I then cut, hammered, drilled, and assembled the conduit and PVC tubing as shown. Then, I just drilled holes into the stationary platform of my trusty "Workmate" for the "U" bolts and fastened the whole assembly with the wing nuts underneath and
PRESTO, I had a portable paint stand! The hitch pins are really just for insurance so that the conduit holding the model can't work it's way out of the holder as you're spinning it around during painting,
really ruining your evening. You can pop the hitch pins out to slide the model out of the holder if necessary, and the whole works goes on and off of the "Workmate" in a few seconds.