Really nice interview with Robert Downey Jr. with EXTRA below.
Downey talks Sherlock Holmes: Game Of Shadows, and mentions how he would come back to do a third.
Note: If you watch the video, there may be potential spoilers as to the ending of the movie - especially if you are not familiar with the character.
Downey also talks about doing Perry Mason, which sounds as if it's a definite go. First, he says he has to do Avengers and Iron Man 3.
Speaking of IM3, Downey offers up that it is the best script that he has read in 5 years (around the 5:40 mark), and talks a little about The Avengers as well.
"Iron Man 3 is probably the best script I've read in 5 years, which is so funny. I mean things have come so full circle, that like a genre super hero movie can acutally be the most artistic bit of writing I read. But I think Avengers is something that I think the fans are really looking forward to, and so I'm excited about that. The third Iron Man to me is an oppurtunity to really just go back to the kind of storytelling and character exploration that made the first one good."