Hi JNS101879,
I would be cautious about considering Custom Sleep Design. While they used to be a member here … they ran into some financial difficulties and their business has been on hold for some time and they no longer have a showroom. You can read more about this in this topic (including my reply earlier today).
The Flobeds vZone also has customized zoning and the zoning arrangement can also be further customized before and after a purchase (see post #4 here). As you probably know they are also a member here and I think highly of them.
Post #21 here (which is one of the links in the tutorial post) includes the other online members of the site that sell customized component latex mattresses that include a wide range of designs, options, prices, and return or exchange policies.
Phoenix