There is a good reason why these are so scarce. They are a major pain to get a wheel in and out and buttoned back up. I can imagine many of them were discarded right after the first flat repair. A wheel fits just fine laying in the bed, and doesn't move around much at all.
I have side mounts on two of my trucks. If I didn't, I would pull a cable hoist model from a modern truck from the junkyard.
