As people said the obvious choice would be 4th Disciple, he's selling beats on his Facebook and Twitter all the time.
Also Madlib's beats are crazy, uses crazy samples and layers. Some of his shit is so obscure, he kinds reminds me of RZA in that regard.
Also, Sin should check out this dude from NY called Confidence, he's a crazy producer, still comin up, but his stuff reminds me of a cross between DJ Premier and RZA.
Check it out: