Yeah, belt colors in BJJ vary a lot between schools. I was curious about "Green Belts" as well as I have a Facebook Friend who attends ATT West Palm Beach and tested a few months ago for her green belt. Sure enough, there are BJJ schools giving out greens between white and blue belt to mark progress. Belt progression for kids under most Gracie affiliates have various combinations of white, yellow, orange, & green. Royce wears a Navy Blue Belt instead of a black belt to honor his father, but still promotes the standard belt colors (link to video below; we're a Royce-Affiliate school and I can attest that he does, indeed wear a navy blue belt when in the gi) In all honesty, in the words of Mr. Miyagi: "No need belt! Use rope, hold up pants!"
http://www.youtube.com/watch?v=q9nDX...layer_embedded
http://www.youtube.com/watch?v=q9nDX...layer_embedded