Fabric: Try JoAnne Fabrics, Fabric Hut, etc. Los Angeles has more than 50 fabric stores, I would estimate. You want white rip-stop nylon fabric. Not sure what kind of sticks you want: solid fiberglass rods would be okay. If you have an existing speed ring, then the diameter and depth of the holes will determine the diameter and size of the ferrules that will be inserted into the speed ring. Ferrules are available at fishing rod building shops, which is my next suggestion--a custom rod builder could help you with ferrules that will fit, and they need to be reasonably loose-fitting where they go in to the speed ring--the flexion of the rods and the weight of the softbox will ensure that the ferrules stay in the speed ring. Low-cost, solid-core fiberglass ( which is actually a trademarked name which is properly spelled Fibreglas, BTW) fishing rod sections would make ideal rods, simply ideal.