Matt Boomer has apparently got the role of Mr Grey.
Nothing's been confirmed. I don't know much about Matt Bomer but, from what I've seen of him and know of the books, he does look more suited to the part than other names being suggested.
Oddschecker has the current cast favourites as Alexis Bledel, whom I've never heard of, and Alex Pettyfer, plus Kim Cattrall as Elena Lincoln. I think it's more likely to be lesser-known actors though, as I could see such a film being a career-killer!