The crew over at Filmschoolrejects.com seems to have found the Captain America cameo everyone on the internet was talking about a few months ago.The scene is during the Antarctic walk that Banner is making, and YES he turns into the Hulk and an avalanche happens. There a blow up of the screen cap that shows the colors and shape of the shield and a faint shape of Captain America’s body. I am somewhat skeptical but you can decide for yourself HERE.
