I was watching the anime recently (from ep 1) and saw at least 2 other black dudes. (not sure if this is in the manga too.
The first one shows up when Shikamaru thinks back to how Chouji was bullied and ignored while they were playing hide and seek. In the crowd there was a black kid with a Fresh Prince high top fade.
The second one is when Naruto Jiraya and Sakura go looking for the hidden mist village to find Sasuke. Jiraya is attacked in a town by ninja's who operate a brothel and rob the customers. One of those ninja's has a big afro and we see him a few times during those scenes.
So at least 2 black dudes.
guess so, but they've never been featured prominently.
and btw, i think your sig's too big. not too sure, but...you'd better check the rules, just in case.