Well, another option (it won't be cheap) is if you have a camping repair place near you. Maybe check with your REI equivalent to find someone. I have place near me, and I am sure they would sew a custom bag to my exact specifications. The could do cool things like put zipper pockets on the outside and put detachable straps, etc. They could even sew in velcro dividers which are moveable on the inside, I'm sure. If there's a place near you - and it is worth the money to you - then start designing!