I'm not seeing any two disc Steelbook editions anywhere even though we got pictures of it. I've checked Circuit City, Best Buy, Wal-Mart and K-Mart. Circuit City seems to have a Standard two disc with a Joker cover. It's the "Why So Serious" poster, but I can't tell if it's just a cardboard slipcover over the regular two disc case.
What sucks is the two disc (Standard and BluRay) has the awful Batpod cover art as opposed to the burning Bat Symbol art from the final movie poster. They are using that awesome cover art for the one disc. WTF?

And
Joe is right about Target. Only Target stores seem to be carrying these exclusive mask cases. I'm surprised they didn't do one for The Incredible Hulk.
Promos
Best Buy is giving away a Joker playing card with the purchase of TDK. It's the card from that last Joker promo pic. It has Batman on it instead of the joker from the playing cards in the film.
K-Mart is giving away a 2009 TDK calendar with purchase.
Circuit City is giving away a TDK journal (?) with purchase of the two disc (Standard and BluRay).
Wal-Mart has a package that includes a comic book and a Two-Face coin. Very cool. The problem is that the gift set is only available
with the standard one disc, not the two disc or the BluRay. 
Also, Wal-Mart is selling the gift set in both Widescreen and Full Frame versions. Who the fuck is buying Full Frame DVDs?
This is the gift pack at Wal-Mart with comic book and coin.
