I actually know this one brony rapper friend of mine who's also a really close collaborator of mine.
I told him about your post, and he seemed interested in assisting. He asked for me to post on his behalf.
His name is Divine Arcane
[some examples of his work can be found here]
https://www.youtube.com/watch?v=YdCy4GdiEZg
https://www.youtube.com/watch?v=tom2Z2UdRxM
https://www.youtube.com/watch?v=O-w9nNf7HT8
Our preferred method of contact is Skype, if possible.