It's happened with books I've uploaded in the past. I found one copy of my Kim at Amazon that still had my title page in it!
There really is little that can be done. Public domain is public domain.
Some countries offer a 'typographic copyright' over the physical page layout, but I don't think there's any way to tell if you'd win if you asserted that it must also apply to ebooks.
Even including text in your copy that the book was formatted by XXX and available free at MobileRead won't stop the rip-off artists.
With public domain books it's definitely
Caveat Emptor. Given castrov's command of English, it's fortunate for his customers that he didn't proof the books himself.
