Well, this hero appeared along with Namor, Juggernaut, and Colossus in the background of the captured and imprision heroes with "super-strength" abilities in Marvel Universe: Avengers: Earth's Mightiest Heroes #4.
If anyone knows who this hero(ine?) may be, let me know so I can create a page for her/him.
EDIT: I don't think I should have darkened the stomach area. So don't think of it as a belt, but more like the color of the rest of her/his body.