If you've got a local source for strapping and buckles, make one yourself. I've found that it's the best way to get exactly what I want. If the belting is too soft it tends to fold up when tightened. It's hard to find a commercial, nylon webbing belt, that has all of your desired features. It's easier to find a good backpack.
Fortunately there are good sources in Berkeley, where I can get to them.