As far as chameleons go, they are totally isolated from other lizards in respect to their pigmentation. They have the ability to change color due to expanding and contracting color cells within their skin. I believe it's something like that. I agree that we might not see a solid blue crested just like we may never see a bright green crested (live the Naultinus and Phelsumas). But there are always intermediates, and it's just something to look forward to.