After seeing the promos for the new Las Vegas show, I think Dennis Quaid could be a good hero type. He plays the sheriff in the new show. But he isn't young. At one time, Glenn Ford should have had that role.
As for Lucas Davenport, the easy choice to play him is Thomas Gibson, the lead FBI agent in, "Criminal Minds." He's the right age, and the makeup people can fake the facial scar.
I'm writing my first novel, a detective thing. I needed to visualize my characters and have pretty much decided on a young Robert Redford sort as the detective. If it gets published and Hollywood calls, I'll tell them to look for someone like that. Alas, I don't know of any such actor. All of those with the right "presence "are too old.
Thomas Gibson could also play Stuart Haydon if David Lindsey ever sells movie rights. I did see the movie of his, "Mercy", and Petra Whatshername who played Nikita was good as Vickie Kittrie, but the movie was too PC and they filmed it in Canada, not in Houston, TX . The lead detective was a woman, not Haydon, another grave PC flaw. The Modesty Blaise movies and the TV show were really bad. They just weren't up to the excellent books or to the comic strip, which ran in about 53 countries. In the USA, only the Detroit Free Press ran the strip, which was too adult for most US "family values" readers. And I think they sometimes had to have the artist dress Modesty more, uh, modestly.
I think the political and personal orientation of many in Hollywood prevents them from casting correctly, in many roles. I think Richard Dreyfuss was particularly bad as the icthyologist in, "Jaws." I read the book and he was nothing like the character. But Redford and Streep were pretty good in, "Out of Africa." Redford really looked a lot like the real white hunter whom he portrayed. And Klaus Maria Brandauer was good as Baron von Blixen.