For the moment I've only been playing around with setting and hardening gelatin, played with the idea of gelatin on it's own, but it tears way too easily.

Making crude cellulose acetate, and dissolving and setting and evaporating it is fairly simple process, you can make whatever thickness you want, but you can't exactly make a roll that way, but you could build a very large trough, or long trough with a sheet of window glass. You can make even better acetates with the addition of acetic anhydride.

Eventually I would like to try my hand at coat with an array of fine spray nozzles over a moving transport through a simple machine, but I don't know yet.