Would you consider a Mangalarga Marchador? If so, I can give you contact information on two people in Ocala with some good horses. A lady in South Carolina has a very nice mare for sale that she's ridden in some short endurance races. I saw the horse in Ocala last month and it's a nice animal. I don't know what she wants for it.
I've also got two mares for sale, along with some youngsters not yet under saddle. But I may be a bit far way for you here in East TN.
To be blunt, you'll pay more for an MM horse than you will for a Walker. But, IMO, you'll get a much better animal than the average TWH found in the U.S. today. I left the Walker breed 13 years ago for a bunch of reasons, and one of them was the general poor quality of Walkers as horses.