After bunch of internet and data problems where my local group gathers, I lost all save data for my profile. This really bites, because now I have to build myself up again. I at least have two custom slots made again, but it'll be a long time before I'm back up to all 6. I also lost some protags that I highly doubt I'll ever get again (like a 5-person kill). On the plus side, my kill/death ratio has skyrocketed. I also just might get more games, because who would expect this single-digit level to have the skill of a 99? Still, I like to be accountable for my history, so I will forever feel like I've cheated even though I didn't do this intentionally.
Have you recovered your gamertag yet? We save everything in your profile so when you recover you should have all your MNC stats. We don't have save files.