This page on the Steam network suggests the Vietnam expansion for Bad Company 2 will be out on December 18th, at least on PC.
Hopefully Map Pack 7 will be out before then! Thanks Mike for the heads up!
Update! MP7 is out tomorrow and Vietnam is out on the 21st and 22nd according to this post! Wooo!
Finally something to look forward to! My only concern is that Dec 18th is a saturday and most games come out on a tuesday. although, maybe dlc is different