Clamp storage systems

It seems everyone has a different method for storing his clamps. For too long, I have kept my clamps in a mishmash of ways in various parts of my shop. I have never liked it and decided to organize them this week.
My biggest problem was finding space for them until I had the revelation that there is unused space behind my door. Its not very deep — a little over six inches — but perfect for clamps.
If you would like to try (or modify) any of the clamp racks I came up with, here are plans: