How about Black Star? I know you said Mos Def an’ all, but still…
You should check them out. They have two albums, the first one (The Psycho-Social, Chemical, Biological, and Electro-Magnetic Manipulation of Human Consciousness) is nearly impossible to find. You may be able to find pieces of it on your favorite file sharing software, but I’ve never even seen an original copy of it.
The newer one, Violent By Design is not as hard to find, but it’s no walk in the park, either. Some label really needs to reissue both of them.