Apparently Marvel are considering including shorts before their main films to launch their more obscure superheros:
http://www.empireonline.com/news/story.asp?NID=28182
Sounds like it could be quite cool. I find there’s a certain appeal to watching a film about a superhero you’ve never heard of. Not sure how they’d work it with length though. A pixar length short would surely be too short but then a 20 minute short might put off some of the general moviegoers. :?