Where can I find a wedding dress that looks like southern belle meets saloon girl?

I am getting married in a few months, and have an idea of what I want my dress to look like. The only problem is that I can't find anything like it! I can find southern belle costumes, but those are generally cheaply made and are not available in all-white. If I search for "western wedding dress," I don't get the results I'm looking for. Where can I find a dress that looks like Dr. Quinn's?