I decided to record the youtube video where they played Jay-Z lyrics backwards to find him saying "666 Murder Murder Jesus 666" and played THAT audio backwards and found what appears to be absolutely nothing. I even slowed it down so that it sounded to have even the slightest remnants of actual music in the first beat and it sounds nothing like English. Here's proof.
Original video with backwards evilness
Audio from above link played backwards
Shit, I don't even hear a noticeable beat pattern. =/