No, I'm not making this up. A guy in New York started a website called www.polka-rap.com which, unfortunately, doesn't have any music on it. I asked why and he said he's too busy and apparantly doesn't have much of a musical background. But if anyone out there wants to make some rap/polka tunes and send 'em his way, his name is Robert Pierce
(email@example.com). They can be originals, or mash-ups, where you take other artists acapellas and put 'em over polka recordings. He'll host them on his site.