Marvel Studios did not dedicate a lot of time or presence to The Avengers at San Diego Comic-Con. Their booth had elements of a S.H.I.E.L.D. helicarrier command bridge and we saw some "agents" standing around but that's about it. Props for Iron Man and Captain America were on display but nothing really for The Avengers.
What Marvel did do was hand out mini posters with concept art for the individual members of the team in the movie each day. "Assembling" them together gives the complete image (courtesy of Bleeding Cool).
You can check a full size, high-res image by clicking here (if that still doesn't work, copy and paste this link: http://i.imgur.com/VQgzK.jpg).
What are your thoughts on their looks? Do they look mighty enough for you?