Answer: Try contacting the California Cooperative Rice Research Foundation at http://agronomy.ucdavis.edu/ricestation/ccrrf3.htm
I think they'd be your best bet for finding appropriate seed. If they can't help, try the info below.
Here are two places that sell Oryza sativa; both are retail but they may be able to direct you to their suppliers:
Southern Exposure Seed Exchange, PO Box 170, Earlysville, VA 22936, http://www.southernexposure.com
V & J Seed Farms, Inc. P.O. Box 82, Woodstock, IL USA 60098
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