If you really want to talk about badass movie combat units, you have to go back to the old days when leading men were made of steel. In 1967, The Dirty Dozen was released and remains, to this day, one of the foremost instructional videos on total Nazi ownage.
The Dirty Dozen was a team led by Mr. Movie Badass himself, Lee Marvin, and the U.S.A. military-grade murderers included Jim Brown, Charles Bronson, John Cassavetes,and Donald Sutherland - with guys like Ernest Borgnine and Robert Ryan kicking them in the ass just for good measure. This team was SO badass that certain members (Brown, Bronson) carried their tough guy images into the next decade.
If you aren't into the classics, or consider the Inglourious Basterds to be the foremost experts in the "Nazi killing business," then you need to guess again and snatch up a copy of The Dirty Dozen.