A live action Attack on Titan project was first revealed before the anime, but is now slated for 2014. I'm guessing that it's going to feature an all Japanese cast. It was looking for locals in Itako in play extras during 2011 filming, before the project lost director Tetsuya Nakashima. Still, Japanese fans have had some fun putting together a (mostly) foreign dream cast for the film.
Now, in my opinion, the picks circulating Japanese blogs range from interesting to plain bad, but it's still a thought provoking list.
Eren - Logan Lerman (Percy Jackson And The Olympians)
Mikasa - Lina Ohta (presumably suggested because she's half Russian)
Jean - Dane DeHaan (Chronicle)
Marco - Eddie Redmayne (Les Misérables)
Connie - Javier Hernández Balcázar (pro soccer player)
Sasha - Kristen Stewart (Twilight)
Christa - Chloë Moretz (Kick-Ass)
Ymir- Anna Christine Speckhart (model)
Levi - Edward Furlong (Terminator 2)
Irvin - Chris Evans (Captain America)
Reiner - Alan Smith (another footballer)
Bertholdt - Julien Kang (Korean drama star, brother of MMA fighter Denis Kang)
Annie - Amanda Seyfried (Les Misérables )
Bearded Titan - Richard Stallman ( software freedom activist)
Who would you cast?
Source : Crunchyroll