Try The Rice Factory, a rice importer in New York state. They import prize rice from Japan, in refrigerated containers. It's a clear step up in quality from anything grown in California.
Well yeah, but you're comparing steak from the blue ribbon cow to Tyson, I sure hope they win. You might still be right about regional quality but you should at least compare the best both have to offer.
I would be amazed if rice grown by Japanese immigrants like Koda or Tamkai couldn't reach the level and it really was the land that made the difference.