Try God Save the Queen Fashions (http://godsavethequeenfashions.com/). She's been posting a lot of pictures of leatherwork on Facebook (http://www.facebook.com/gstqfashions) lately that fill me with glee. Given her latest Facebook post, I would strongly recommend waiting until after Dragon*Con to email her though.

(As a side note, real leather doesn't come on bolts, but is bought as hides. The stuff that comes on bolts is all imitation vinyl, pleather, that sort of thing. If you want a faux leather costume instead of real leather, it's likely to cost less.)