Here's my thought process:
1) Buy Dead Money
2) Load up the game; get the infamous menu bug and I'm thinking... huh...
3) Open up LOST, see that the Dead Money .esm is present, activate it.
4) Tried starting New Vegas again and it does the 7gb dl and I'm thinking to myself.. "You have to got be kidding.."
5) Then I realize, "Oh snap! My data folder! MUST PRESERVE!"
6) Turns out it's 11 gb's and I'm just like... "Please don't delete that.."
7) See this post:
Saw a post on the Nexus somewhere (chat, maybe?) that said it looks like a 7gb dl but stops at like 324 MB and you then have the .esp.
8) Myself: "Oh well" and cancels the copy.
Download was done for me at 347.0 MB on the dot. Maybe I'll copy my data folder anyways one day.