Here's a random though...The Aquabats? Their TV show is getting kind of a cult following, and they've been around for 20 years, so it's not like there's any lack of material. I don't think any of their albums are on major labels, technically. Plus MC Bat Commander did vocals on "This Gigantic Robot Kills" by MC Lars, which made it through RBN, so maybe he's already familiar with RBN, maybe?
Just to recommend a few songs:
-The Shark Fighter!