Erich, if you're interested in studying the art of scrolls and leaf structures, I would recommend the book "Advanced Drawing of Scrolls" by Ron Smith. Although written with a singular focus towards firearm engraving, as Jim suggested, firearm engraving is an art form in which acanthus leaf design is still a very important element.
It's not an inexpensive book by any means, but it's worth every penny if you really want to learn how to draw scrolls and leaves. It can be found at GRS.
You're work is absolutely wonderful. Your granulation is astounding, both in it's use and execution. As Jim also said it's nice to see attention to detail like your azures. The bar keeps rising.