Nice work M.M. I've always wanted to try this but have never taken the time. I've seen some very expert results of this, usually with celebritiy photos, on other forums. There may even have been a thread of it here once. If you want, walk us through your technique. I might even supply some celeb pics and let you do your best with them. 
I know the results will vary widely, partly based on the quality of the photo, and what fabric was actually used.
Here's one of Rachel Bilson for starters. I have 2 or 3 x-ray versions already, let's see your result. If you need a larger version, I'll try to find one, but I think they used one this size. (For anyone thinking this violates a celebs "privacy": they've known for years that some flash cameras can see thru fabric, yet they continue to wear thin materials. Besides, this usually only works on pics they posed for, like this)