A film critic with the Twitter username @thefilmcynic just saw a screening of The Avengers in the US and has confirmed that there IS a second post credits scene for the US release. No, I'm not talking about the mid-credits Thanos reveal... this is a scene after all the credits. What is it?
It's the entire Avengers team post-battle quietly eating shwarma for about a minute, no dialogue. And if you're wondering, it's Bruce Banner there, not Hulk. For those that don't get it, it's a reference to a line Tony Stark says in the movie about how he knows of a shwarma place nearby.
This is according to @thefilmcynic on Twitter, so he's my source on this. He is a professional film critic, and would not lie about this.
https://twitter.com/#!/thefilmcynic