You are correct that black is not a standard "acceptable" color, but if you were to follow the lineage of his dogs, he has produced black pups. I've been to this guys farm, and its the real deal. Dogs all have papers, dogs are actually more impressive in person (especially Mandela below), and he def has a lot of knowledge on them.
Pic is of the sire. 170lbs 30 in at the withers.
Dam on the left at 8 months. At maturity she was 130lbs and 30" at the withers. (Male kangal Dogo x boerboel)
I know it seems like mad scientestry, but these are some very impressive dogs. I like big dogs but i will not sacrifice size for agility/athleticism or health. I don't want a lawn ornament. Plus I'm not really into purebred/inbred dogs (not stating all purebred are inbred).
Here is a link to the video of the litter from which mine came from, it shows the dam and one other black pup that was produced.
[video=youtube_share;HFi1mYS6hN8]http://youtu.be/HFi1mYS6hN8[/video]
I'm not trying to stir the pot i just wanted to give you the full details. Sorry if my response reads the wrong way...