I see there was some featured in Playboy too:
http://en.wikipedia.org/wiki/Caroline_Cossey
http://en.wikipedia.org/wiki/Amanda_Lepore
There a private company decides a niche and style, and puts there who fits it, for simply fit the niche. I still think there should be freedom for a cam company to have a site with girls only, and so to declare in advance "girls only accepted", without risk of being bring to human rights court by any transexuals. Or, you would bring to court gay sites for not allowing girls there, or mature/granny sites for not accepting teenager models, or a BBW site for not allowing thin girls, or a redheads site for not accepting brunette, and so on. You can question certain companies miss completely a certain niche, but at same time other companies exist who have that missing niche as the only niche, so there's space for everyone. Of course I can tell this to the models we decline and they still will call us morons doing crime against humanity
On a side note it happened so often I go to filipina cam sites I click a few girls I seem to like most and it ends up they're ladyboy really, so it may not be an issue of looks, it is just if you say to your users you provide girls only, that would be false advertising, should label them as ts in first place.