www.clips4sale.com/18060 (Darksidespankings) is great if you like African-American strippers / pros (which is very much the focus of this site.
"African Spanking" -
www.clips4sale.com/8798 is rather different - the girls are younger (the youngest models are 18 and 19; up to mid 20's). They are also all born in Africa (or, in one case, the Caribbean) - and often grew up there, only coming to the UK as students. In many of the films the spanker lets the girls talk about their experiences of corporal punishment when growing up.
The other unique feature of this site is that the girls are without exception amateurs, often being spanked for the first time on camera - and in some cases the first time ever.
There have been quite a few updates recently so, if you are into black bottoms getting spanked, and you haven't visited this site in a while, it is certainly worth a look. The more recent spankings are in the nude generally...
Also - go to this site if you really still feel that black bottoms don't mark well. They most certainly do (and with the lighter skinned models you can clearly see a lot of red colouring as well).