I am looking for direct manufacturers and suppliers of stone and shell
cabochons in the 40X30 mm oval and 30X22 mm size. I use cabochons as
the main centerpiece of the bracelets and pendants I create.

Please see my websites for a list of stones and shells I use:

http://www.steelnstones.com/stonespage.htm
http://www.steelnstones.com/shellspage.htm

I have used firemountaingems.com, an Indian jewelry supply company,
and a couple of the others for the past three years. My goal is to
bypass the middleman and go directly to the source so I can purchase
stones and shells for the same price that that the above mentioned
companies buy for. I understand that most retail suppliers buy bulk
from many different sources. I am wondering what quantity I need to
buy in order to receive a bulk discount.

A great answer should list all available wholesale manufactures and
suppliers contact info (name, address, phone number, website if
available) with the stones or shells that they offer. A price list
including quantity discounts would be helpful. Please request
clarification if need be. Thanks.

A very good supplier is;
J.P.C in Miami, Fl. Their # is 305 373 8255