Plenty of people say they have black shemales - but if they're black and Brazilian, they're not going to sell as well as black N.Americans.
http://www.black-tgirls.com - has been running for 13+ yrs and is the authoritative website in this niche.
http://www.black-shemale-hardcore.com - spin off site from above and brand new. Currently converting in 1:152
http://www.franks-tgirlworld.com - different types of girls from worldwide but a lot of black content.
http:///www.shemalepornstar.com - as above.
All at
http://www.groobybucks.com