Hi dndcorzi,
The better options or possibilities I’m aware of in the Nashville area are listed in post #2 here but you would need to call them because I don’t know the specifics of the mattresses they carry on their showroom floor.
If you are open to driving a little further then post #18 here centered around Evansville, IN includes several local factory direct manufacturers that should either have or be able to make you what you want. Post #2 here also includes two factory direct manufacturers in Chattanooga, post #2 here includes two factory direct manufacturers in Knoxville, and post #57 here includes Royal Bedding in Pelham, AL who I think very highly of and could certainly make you a two sided version of what you are looking for.
That depends to some degree whether it’s glued or not (it would be much more difficult if it was glued) but post #2 here and the posts it links to have more information about “mattress surgery” that may be helpful.
Phoenix