Seymour, if I new such a source I wouldn't use my framers make appropriate boxes for our foto frames. Thin cardboard, shiny screaming gift boxes are available but they are not suitable for frames. They are made with cheap Indian gift trinkets in mind. Besides, there is a minimum quantity involved and I suspect that you need just a few dozens of them.
In case this may inspire you, one of my largest photo frame clients is ordering photo frames without boxes exactly for the purpose of avoiding the "commercially, mass produced" feeling which most gift boxed items are likely to induce in many people's mind. Is it possiblle that a different packaging would compliment your frames in a more flattering way than cheap gift boxes available out there?