I know I've been a big fan of 
Nathan Petrelli Adrian Pasdar as Marcone, but after watching the 
Castle rerun "Heartbreak Hotel" today, I'm agreeing with the opinion that Richard Burgi could do a good job.  He plays a casino boss in the episode, and comes across very Marcone-like.

Pair him up with John Cena as Hendricks...

...then we cast Alyssa Sutherland as Gard...

...and Angie Harmon as Helen Beckitt, and we're good to go.
