I looked for *months* for fabric for the top when I made my Dany cosplay
-- in fact, it was the reason I started this thread! -- and found absolutely nothing that was even close. I ended up knitting the fabric from scratch, then weaving bits of string and yarn through the knitting to get the look I wanted (there are pics of it in-progress in my profile, if you're curious). In the year and a half since then, higher-rez pictures of that top have been released, which to me make it look like the top is woven from a combination of thin leather strips and horse hair, which makes sense given the Dothraki society. But in the years since I started looking, I've never seen any commercial fabric of any type that would be a reasonable match. I think a lot of people end up using burlap, at least as a base, but since the fabric for the top is one area where all Daenerys cosplayers struggle, it can also be a chance to do something creative that no one else has thought of yet and stand out from the pack.