Alright, so I checked the Die Rise Xbox leaderboards today. There's nothing that I can see on the 2 and 3 player leaderboards. On the solo leaderboards, there are two people, and both their player channels have one game of Die Rise on it (roughly 3 minutes.) I tried to watch it, but I don't have the DLC.
What's much more fascinating to me is on the 4-player leaderboards. First off, there are only 3 people on it. Secondly, when you look at their player channels, there are a handful of games of TranZit. On Nuketown. The map preview shows the checkerboard thing everyone is familiar with, which leads me to believe it's hackers, but you can watch them play TranZit on Nuketown and they just kinda goof off for a couple minutes. And all of these TranZit on Nuketown games occurred after the patch was released. I'm currently in the process of watching all the Nuketown games and looking for things.
The gamertags are: FuRz Thomi34, and it looked like the two others were in a clan. It looks like they all got taken off the leaderboards now... I'll update if I find anything new. I originally posted it in the TranZit discussion, but I feel like it may pertain to Die Rise as well, so I posted it here.