I'm a tinkerer. I can't help it. I built one of the PVC racks that was posted here where the guitars sit on top of a dual rail with the necks hanging down. It worked great, but after a few months I wanted to try something different. Yesterday I was looking at it and thought, hey I could convert that to a leaning rack like 1 of those travel guitar cases. So today I went at it. I'm sooooo happy with it! Thought I'd share in case it helps someone else. If you build one, you don't have to follow my dimensions exactly. Do what's right for your needs, tweak it, make it better...

Notice the front lower rail is higher than the back rail (only by 1 inch), but this make the guitars lean back against the top rail. This is key!

At first I did a quick assembly without the elevated sides. It worked great, but decided to put them to prevent a cbg domino slide if my crazy dogs rammed into it while wrestling.

The whole thing's made from 1/2" PVC. I inserted a 1/2" aluminum tube inside the front lower rail which bears all the weight to keep it from bowing. Works really well & keeps it light. I tried a dowel, but it didn't stop the bowing.

Hope this helps!