I guess there's not a lot of John Carter cosplay in conventions. Many reasons for that, of course the movie is perhaps not popular enough, but also the costumes are very revealing. There are pneumonia dangers and the risk of being ridiculous of you're not physically fit! So the example below deserves some recognition!
John Carter's name is Jim Gillespie, and Dejah Thoris, whose costume combines many concept arts other than the movie's, is "The Chainmail Chick". She has a Facebook page with many examples of cosplay: