I agree with Rob on the Imax thing. The whole point of Imax is a huge screen and 3D. I don't see why anyone would want those shots on a DVD. Even if you had the biggest home theater setup on earth, why bother?

On the other hand, maybe the dearth of features is simply because Nolan didn't shoot that much extra stuff, especially in light of the Ledger death.

Probably the most entertaining thing they could have done was get Adam West and Jack Nicholson to do a voiceover commentary, moaning about how Bale and Ledger "stole" their characters.