I wasn't sure about this idea at first, but I really like the idea now. It hink it's kind of like the old 'Marvel comics Presnts...' anthology comic, where it would have a lead off strip about a major character(Wolverine, Collosus etc)that was an ongoing story, and then the rest was 8 page short stories that featured lesser known Marvel characters.
Thinking about past movies, and what ten minutes would have been ideal to get the audience interested in a character in 10mins...
Wolverine - easy, the intro we got...cage fight and 'Get out of my bar freak' scene, a perfect 10mins that surely would have got him a greenlight.
Spider-man - ok, keeping it realistic with what they would have done for a 10min demo, without it being too expensive...the dining hall scene in the high school and fight with Flash, that would have went down well I think.
Blade - as someone has said already, the intro we got at the rave.
Daredevil - Josie's bar clear out
The Hulk - the scene when he Hulks out after whatshisface tries to pin him down in his house.
They can do a great scene without having to spend too much on sfx if they stick to real stunts and a minimum of CGI basically. Stating the obvious relaly, but thinking about all those scenes, it could be done very well for any character.