Hi Restinrett,
You will probably need to work with a local manufacturer who can make custom sizes for their mattresses although in some cases a retailer may also have a good relationship with one or more of the manufacturers they deal with who can also make custom sizes.
The better options or possibilities I’m aware of in the Naples / Cape Coral / Ft Myers area are listed in post #2 here and there are several manufacturers in the area that should be able to make custom sizes.
I would also make sure you’ve read the tutorial post here so that you know how to avoid buying a mattress that is the right size but uses lower quality materials that won’t last.
Phoenix