For slick, beautiful fighting I don't think anybody could touch JCVD. Other than Dolph Lundgren, perhaps.
Dolph could do the good looker blonde bit too. If you want a blonde, handsome, brooding Skilgannon.
If you don't mind the actor not being a hardcore martial artist, then Brad Pitt would be an obvious candidate.
Considering the things XVX-Dread & Mahayana said about Skilgannon, i.e. someone fighting his inner demons, someone slim & aesthetically muscular etc., how about the footballer David Beckham?
David is not yet an actor, but I believe he can be transformed into a decent one with the right coaching. He's not that talkative, but maybe that could turn out a plus in his favour, if his Skilgannon is presented as a reserved character.
Eric Cantona, another ex-footballer from France, is also an actor now. Now, he is one who can definitely play a brawler. His famous kung fu flying kick during a game for Manchester United, aimed at some yobbo spectator who had been needling him continuously, is now part of British football legend. Maybe Eric could play Druss.
Dwayne 'the Rock' Johnson and Steven Seagal should also be auditioned for one of the other Gemmelian hero roles.
There's also a new bloke named Scott Adkins. He played the lead role in a recent American-ninja movie. He looked quite proficient, I thought.
Then there's British martial arts actor Gary Daniels. He's not bad either.
Orlando Bloom? Haven't got anything personal against him, but my view is that he's a bit too cutish to play a macho, swashbuckling swordsman convincingly.
Keira Knightley, Milla Jovovich, Kristanna Loken, Natasha Henstridge should play the Gemmelian girls.