Well there are 2 good nurseries/garden centers in Tupelo that carry large specimens, not sure exactly about camellias, but surely. I would call first to find out their inventory and prices.
Mid-South 662-842-4193
Philips 662-842-1267
and then there is Dry Run in Jumpertown, no. of Tupelo, that is a grower and more of what I would call wholesale, not set up as a garden center per se. 662-728-8884
All have good quality and good service in my opinion.
I've never been to "gardens oy vey" in west Tennessee but have always wanted to go, not sure if that is in your desired travel area, not sure what plants they carry, you can google them on the web.
Laurie

Probably farther than you want to go but there are several great growers in the Mobile, Alabama area. Also in Fairhope, Alabama. (You could work in some time at the beach, too. :)

I love camellias, and I agree that it is tough to find good sources for them. I just kind of haunt all garden centers within driving range this time of year. You never know what you will find. And, I mail order too. Greer Gardens in Oregon has a good selection. Then there's Nuccios in California. Their selection will knock your socks off. It's a family run business (and world famous hybridizers) You have to call them in person and request a catalog. It took about 3 weeks to get here. But their reputation is stellar. I am still trying to narrow down my list. :) And then, there's Camellia Forest in the Carolinas. They have a great website.