I recently came across some fashion plates from the early 1900's that were fairly high res, AND in the public domain, I downloaded several dozens of them. (You never know when they might figure into a design project.)
But, they also fed right into my ongoing search to find things to apply my repeating patterns to. So, I opened a fashion plate in Photoshop, extracted the black outline, copy and pasted it into Ai, and used Live Trace on it. Live Trace almost always needs quite a bit of cleanup to get rid of its distinctive weirdness, and this time was no exception.
But when I was done, I filled in all the negative spaces, and viola!