There is also buckram, it is a type of fabric used in book binding. You can soak it and make into a shape and it'll restiffen or so I've read. Like for mask making and other sculptural projects. I bought a giant roll of it but haven't tried it yet. It's supposed to be close to stiff stuff but more economical. Looking at it I'd say it is a much looser weave that is still fairly stiff, I planned to use it with ultra suede. My guess is that stiff stuff would be better if you can get it, I'm guessing that buckram will become less stiff as it's handled which beadwork takes a lot of.
Once I try it if it works I'll probably sell it on my website in sheets. I haven't had time to do beadwork in many moons though. If somebody here would like to ty it and tell me what you think I'll send some to you. It would be most helpful if you had tried these other things, to compare them.
Ingrid