India
Given how close it is in Asia (by China) and the numerous ladyboys alone you know there is a niche for it. That being said everything sexual is still very taboo in India so being discrete with billing would be an issue - or creating a free site with a "Boss" button would be a must !
http://www.google.com/search?hl=en&c...f&oq=&gs_rfai=
Considering transsexuals are fighting for their rights in the country I would say it is quite the possibility there are a lot of them
Again, probably most of them pretty discrete though !