CHEATER!
Looking great man, you know I follow all your flickr updates too, but its neat how you're cutting the helmet to sculpt over. Smart move.
Also, REALLY convincing me to get my own CNC here. Thats some droolworthy stuff.
If you are looking at casting dragon skin and foam, check out somafoma from smooth on. It's a silicon foam vs a urethane foam like flexfoamit. The silicon foam will bond with the dragon skin without the need for a mechanical bond. Just a thought. And your sculpt is fantastic. I can hardly wait to see how this moves forward.