As far as I know the only faires that still insist on strict clothing requirements are Southern Faire/Northern Faire, and the Arizona Ren faire in the spring.
Crimeny, you still have to take 'classes' to be in S. and N. Faires!
Having worked in the costume department of S. Faire, I can tell you it really sucks having to tell someone their outfit isn't appropriete because they used the wrong kind of material, it's too bright, the color wasn't around at the time, and on and on. I'll never forget the couple that had their outfits professionally made, they were beautiful, except they used this horrible bright blue material. I would have let them go because of the work involved, but my supervisor said no to them. I was thoroughly disgusted with the behind the scenes garbage. Never did it again.