In the Resource & Biz section of my site, I have a page on framers at
http://www.portraitartist.com/resources/framers.htm
I don't know what price range your clients are in, but with some of these places, it's possible for the client to pay more for the frame than the painting. In fact, one artist told me he got more in his commisson on selling the frame than he did on the actual painting!
Eli Wilner has antique frames that are sky high in price, but still wonderful to view.
When I managed Robert Schoeller, we used Abe Munn a lot. On the web, they only sell wholesale. But, as a portrait artist, he was viewed as a reseller and we got the wholesale. I would think it would be the same with most framers.