Ok.... let's get this straight.... MC's do not make mixtapes. If you rhyme over a tracklist of original beats, that's a fuckin' album. If you are rhyming over an established producer's beats from the said producer's catalog and are selling it, you're plagiarizing.
DJ's make mixtapes. A mixtape showcases a DJ's skill in scratching, juggling, mixing and track selection. It is also a tool for DJ's to educate their audience with what's hot right now. An MC can "feature" on a mixtape.
Some of my favorite mixtape DJ's include PF Cuttin', DJ Clue and DJ Premier. Go do your homework. I'm not gonna hand it to you on a silver platter.
Peace to all the DJ's keeping our culture alive...