I have a hunch that the producers may be looking at Goran Visnjic to play Le Chiffre. He would be acceptable (although far from ideal) for the role, and it would explain why his name has come up. Likewise for Ewan Stewart, who is absolutely NOT a candidate for James Bond. I have a theory that the "list of four" may be valid, but that they've been tested for a variety of roles, not merely for the role of Bond.
* Visnjic is testing for Le Chiffre. In the novel, Le Chiffre was of Eastern European descent. No problem there, eh? However, Visnjic stands at 6'4", so they'd have to change the character a bit.
* Ewan Stewart is also testing for Le Chiffre. He's 5'9" and kind of evil-looking, so he'd be more in line with the novel. He sure as

isn't testing for
Bond.
* Alex O'Lachlan is testing for Bond. This much I can believe. He's got the right look, he's 28 years old, and he's Australian.
* Henry Cavill is also testing for Bond. He's the right ethnicity, the right level of fame, but he's too young and babyfaced. So he's probably already been eliminated.
I doubt the latter two will end up on screen. They've probably already been eliminated, hence, their identities are less closely guarded. However, we may end up seeing Visnjic or Stewart next year playing Le Chiffre.