Orlando Bloom for Thomas. Makes sense. Has that appeal to women, has the curly black hair thing. Tall but not abnormally so.
Cilian Murphy for Madrigal Raith. Has that other-worldly, somewhat sinister look. Can definitely see him as a little weasel in White Night.
Cilian is good choice for Madrigal.
But Orlando for Thomas ...sorry, but he is way too short (it says 5'10 on IMBD, ahhh, not a chance maybe 5'8, I've met him in person.) Also he's only 33. I think this artist really has a good rendintion of Thomas, next to the actor from "White Collar," Matthew Boomer. Who is also 33, but looks alot older and his comedic timing is well crafted. I know he's been mentioned several times before, but after re-reading 'Changes', I can totally see it.
With Johnny Marcone, we know he is in his forties.... good looking, but tough, average height (5'10-6')
Now, I would say George Clooney, but he is also too short. And like Chris Noth, both may be too old for the role. Although, Chris Noth is usually who I think of when I think of Johnny Marcone.
However, I found this by an artist that I think works
**EDITED for spelling and to post photos**