Fable Designs ( http://www.ganoksin.com/gnkurl/ep7z65
) makes custom
black ceramic rings (as well as black zirconium, cobalt, titanium,
tungsten, wood, camouflage, carbon fiber, stainless steel, etc), and
they do every bit of it in Utah.
They are wholesale to the trade only and I don't know what their
requirements are, but I would guess that a JBT listing or rating
the minimum. They are very friendly and easy to work with so a phone
call is definitely in order. I am an authorized retailer so if they
won't ship to you, let me know and I'll order what you need for you.
Their toll-free is (866) 847-4647.
Best of luck!