Here's another gizmo I whipped up for holding stuff while painting. It's just a simple knuckle-joint affair that rotates, which I bolt into the arm from my engine lift. It's nice because you can change elevation or set it at any angle and rotate the part 360 degrees. I also use it with shorter connecting rods between the tanks for wet sanding and buffing. The tank stand itself is just some scrap welded up and bolted to one of my old motor stands. Nothing fancy, just old junk (cheap!) re-cycled and put to work. I'm not the worlds greatest painter, and I find that helps an awful lot having the tank in a comfortable position when I'm trying to spray the bugger.
Here is a close-up picture of the knuckle joint: