Well I just couldn't wait. I figured I would try making one and if it was terrible, then maybe I would buy one.
I showed my girlfriend the TAB gear rear bag and asked if it could be replicated. She looked at me as if I had asked her if she was able to boil water and went to work...
To source the cordura, I found and old grocery bag and cut it up and 1" webbing I had laying around for a strap. I had some Airsoft BBs remaining from my old sock bag, so I just transfered the beads to this new project.
Anyways, it turned out great for me and I don't feel I will need to go buy anything pre-made from now on. If I can find more cheap cordura I might play around with some different designs.
Final dimensions are 7.5" L 5" W 1.5" D which gives me a nice range of positions to use it in. The hand strap is a good stolen idea than feels good.
Here it is.