Usually by this time HBO would release an Annie Leibowitz-shot promo picture of the entire cast, which then appears as the DVD cover. The pictures are usually rich with symbolism (none of the characters make eye contact, no smiling etc) and have a distinct look to them. As of right now, there are few of these pictures, but here's what we have so far:
Tony, New York, Ducks
Family in Alley

And of course there's the Vanity Fair pullout of the entire cast, which was incidentally shot by Leibowitz, but none of these above pictures look like they're worthy of a DVD cover. The most artsy one is the one of Tony and the ducks by the Statue of Liberty, but that doesn't have the rest of the cast on it. I wonder what they will do for the DVD cover. Hopefully they'll release something more detailed, as I always look forward to these pics every season.

The picture of Tony with his back facing the Statue of Liberty would nice DVD cover or final poster. Considering, the final season will most likely focus soley on him and his war with New York.

It appears that, according to Wikipedia, the promotional poster for Season Six Part II is the black and white photo of the family in the alley. I've actually seen a couple of them on the net with better resolution and it says "Made in America" in red on it. I guess it's a pretty good promo poster if you really appreciate it.

That Vanity Fair cover was excellent!
I liked the way they had the "deceased" characters in also....morbid mutt that i am

I laughed when I saw Ralphie holding his head. I guess that also proves that Adrianna is dead, not that I had any doubt.