Joss Whedon is having so much fun writing The Avengers for Marvel that he's writing scenes that he knows have no place in the movie. Can anyone say "merchandising bonanza"?
Whedon admitted to the Sydney Morning Herald that he's writing far more material than necessary for the Marvel Studios movie:
Right now I'm working on a movie that's got enormous stipulations and is going to be changing and fluid every second. I've come up with dozens of scenes and lines and exchanges and monologues that I adore that are not going to be in it. But while I'm writing them they feed me, excite me and they ultimately inform the character. It all goes in.
If someone at Marvel's publishing division doesn't read that quote and think that an "Unseen Scenes" tie-in comic with a big-name artist (Say, Bryan Hitch) illustrating Whedon's unmade material would be a good idea, then someone at Marvel needs to think again.