Hi bulge,
Subject to confirming that any retailer or manufacturer on the list you wish to deal with is completely transparent about the materials and components in their mattresses (see this article) and to making sure that any mattress you are considering meets the quality/value guidelines here … the better options or possibilities I’m aware of in and around your area are listed in this post.
There are 3 factory direct manufacturers on the list but I think that Sleeptite would be the one that is most likely to make a custom design that is different from the standard designs that they make and have on their showroom floor (although you would need to call them and make sure).
Phoenix