Most of the black finishes like black chrome are in a satin or matte finish, not glossy.
The "paint" type epoxy finishes, including the new ceramic finishes all seem to be matte.
The Germans seem to have had good luck with lacquer type finishes. Walther used a lacquer jet black glossy finish on the post-war P-38/P1 frame, and CZ has used a lacquer finish on some models.
You might talk to Ford's and Cogan to see what they might be able to do:
http://www.fordsguns.com/
http://www.apwcogan.com/