I would buy scenes of all the mentioned black beauties. Slim black girls are lovely.
I'd like to say one thing though and that is that lighting has to be perfect. It seem to be more difficult to shoot dark skinned women but when you have great lighting nothing beats the contrast between dark skin and cherry pink pussy.
I am also a fan of women who have a darker pigmentation around the asshole. I have heard of girls trying to bleach their assholes which I find ridiculous and stupid. More dark buttholes, please!