Hi Zerbert,
If you are focusing on online all latex mattresses then the mattress shopping tutorial includes a link to a list of the members here that sell mattresses online (in the optional online step) and many of them also also sell all latex mattresses (including component mattresses) that use different types and blends of latex and have a wide range of different designs, options, features, return and exchange policies, and prices that that may also be worth including in your research.
Subject to confirming that any retailer or manufacturer on the list is completely transparent (see this article) and to making sure that any mattress you are considering meets your criteria and the quality/value guidelines here … the better options or possibilities I’m aware of in and around the Austin, TX area are listed in post #2 here.
Phoenix