Well, let's look at raw numbers:
1. You want exclusively black men. That's ~7% of the population.
2. You want men who are probably >8in. That's the upper 98th percentile. To put it in context, if you take 100 black men, only 2 will meet your criteria. So now you're looking for .07% of the population.
3. Now you have to narrow it down geographically. Rural areas are much harder to find black men in, generally.
4. Now you have to talk about disparity - these rare specimens aren't really hard up for pussy. What are you offering that makes it worth their time? Your wife's holes? **Sex is easy for men like that.** You are approaching this situation as if YOU'RE the one in demand when it's the complete opposite.
Personally, I get plenty of offers to bury my dick into women, but I just don't have the time for all of them (or any of them, to be fair. I'm busy.) If you want a BBC bull that meets your requirements, you have to be giving something exceptional to beat out the other offers he's getting.