One of the best (IMO THE best) bonsai potters in the U.S. is in Wilmington (just south of it, in Boiling Springs Lake)
Ron Lang-
http://www.langbonsai.com/ - moved down that way a couple of years ago from Pa. I have been a regular customer of his for going on something like 20 years. I miss not being able to go to one of his kiln openings by driving only two hours. He has been working with Ryan Neil on progressive containers and hasn't been at local shows...bummer
His pots are expensive, but you will not find a better constructed or designed bonsai pot in the U.S. Nor will you find glazes and finishes on pots that are more suited for bonsai. They are not traditional and match native species-- If you have the $, investing in one of his pots (Even if your tree may not be all that), is not a mistake. The pot will be useful down the line, believe me.
If it were me, I wouldn't be futzing around trying to convince non-bonsai potters to make you a bonsai pot. I've done that. Not worth the time or the (sometimes) annoying discussions with potters who don't "do" bonsai. You will wind up with a casserole dish with holes in the bottom and a glaze that goes with ham--or a potter who believes "subverting" their work to be secondary to a tree is beneath them...