Nope, we're haven't discussed doing the DLC. Right now we get between 4-6 people on Mondays and Fridays. We have 7 that would play but sometimes getting them all together is rough. Last night we finished up the 4 player challenges and did the 3 player the night before. I think we're basically more interested in attempting the 6 - 8 player challenges.
I'll add you on XBL and will let you know if anything comes up prior but our sessions regularly go on! It would be awesome if we could get 8 people.