South wont help you too much... go West (really really far West).
Not sure how serious you are about this and / or what your budget
Find a local woodworker that specializes in fine custom wood working and have them design on board, build in their shop and assemble and install on board.
While you can resaw 5/4, there is no getting around paying $35 per board foot for teak
As you are doing a significant amount of work, you might consider using mahogany and 'do it all' considering the cost of replacing teak you can just redo the entire interior
in an alternate wood source as you can redo 30% in teak.
Lye (cooking spray) will age your mahogany.