I've never heard of anything I'd call progressive rap, but there is progressive music that has had rapping and hip-hop elements. I consider Faith No More to be progressive (In a general sense), and they have had elements of rap/hip hop in their sound (Most notably their hit "Epic").

Of course there's progressive rap, even Art rap, but it's not a blend of Prog rock and Hip hop.

This could sound like this : 

Death Grips?

I'm a hip hop fan and i haven't yet heard any of it crossed with what we would call progressive rock. I think the reason this cross pollination hasn't happened yet is because hip hop is a lot like funk and it demands a steady meter rhythmic cadence march thing that doesn't allow for time sig changes and classical / jazz interventions. There is a crapload of really great artistically brilliant hip hop though but it is the one genre of music more than any other that stresses the poetic meaning of lyrics and storytelling over musical w**kery. However that Death Grips probably is the closest thing and if there has been some sort of underground prog vs hip hop thing, i'm all ears :)

Edited by omphaloskepsis - July 02 2016 at 12:03

This does sounds little like it is rap with prog. The thing is, I usually don't like listening to rap because it always sounds the same. I thought maybe the prog gods could have put a spell on it to make it more interesting, but it doesn't really sound any different

The original proto-prog rap song: