HeatVision is confirming previous reports that both Gary Oldman (The Colonel) and Garrett Hedlund (Kaneda) are wanted by Warner Bros. for Akira. Twitch and HeatVision both report Helena Bonham Carter is involved, she's been rumored for Lady Miyako. There are still a bunch of large parts still up for grabs and a fourth actor is now in the mix.
Someone new mentioned is Keira Knightley who is likely in mind for the role of Kei. A revolutionary who ends up helping Kaneda when his friend and fellow biker gang member Tetsuo is mixed up with military medical experiments. Knightley is best known internationally for her role as Elizabeth Swan in the original Pirates of The Caribbean trilogy. She's been itching for a new blockbuster as she's been testing for films like The Dark Knight Rises and Captain America The First Avenger recently. Keira previously played a rough and fast-talking bounty hunter in Tony Scott's Domino, so she might fit well in this role.