Could be some good news if you've ever wanted to see Sir Ben Kingsley play a Chinese jewelry aficionado.
Despite Marvel's denials and unspoken public policy on repeating the mistakes of Charlie Chan films, it seems that Kingsley may indeed have joined Iron Man 3 to play the Mandarin, Tony Stark's magic ring-wearing, Chinese arch-enemy. The news comes from LatinoReview, where they also add that Mandarin won't even be the primary bad guy, saying:
Here's what we can CONFIRM as true (and not from some guy working security on an off-lot shoot): The Mandarin (as played by Ben Kingsley) is a villain in the 'Iron Man 3,' but he's more a veiled threat as a silent partner to Guy Pearce's Aldrich Killian. Killian is the man inventing Extremis and putting it into his "Extremis army" of multiple super-powered individuals.
Earlier this month, Ashley Hamilton and James Badge Dale were cast as cyborg commandos of sorts, so they will likely be the "super-powered individuals" assembled by Killian. And since he's apparently playing this Asian supporting role, Kingsley will probably just be the kooky, myopic neighbor upstairs who's always complaining about how "roud" it gets when Killian has his bionic friends over.
UPDATE: In other Iron Man 3 news, ComingSoon has confirmed we'll be seeing the Iron Patriot armor, seen to the right, in the upcoming sequel. In the comics, Spider-Man villain Norman Osborn wore the armor to play a hero and pay tribute to the recently-deceased Captain America. For obvious reasons, that seems an unlikely scenario for Iron Man 3, so they'll probably just throw Paltrow in there.
UPDATE 2: Turns out it's James Badge Dale in the suit, and TheSuperficial has this photo of it.