I really couldn't find it anywhere else on my own. Of those sites, I checked Warmoth and couldn't find binding listed as a product. Either they hid it or it would be a special order... WD has a minimum order of $20, and I couldn't find binding there either... LMI only has .08 in black and I need .09. Finally, I did a web search on guitar binding and turned up nothing.
Hence my statement that Stew Mac seems to be the only place to get it.
I was thinking of maybe trying pickguard material. It comes in the right thicknesses, the only problem might be getting it to bend, but since it's plastic rather than celluloid I figure you could use more aggressive heat. Oh, and you'd have a lot more joints in the binding, but if you're good at doing binding anyway that shouldn't be a problem.