Hi Eric,
Post #21 here includes a list of the members of the site that sell online and many of these sell component or customizable options that are among the better options available I’m aware of.
Each of these offer different benefits, designs, and options as you will see from their sites but as a group offer among the best quality and value mattresses for anyone who does not have a local factory direct manufacturer’s outlet or better sleep shop with similar value in their area. The extra 5% discount available from these manufacturers to members of this site is a small additional bonus on what are already exceptionally high quality/value mattresses.
Several memory foam options with interchangeable layering are (rather than exchangeable layers) mentioned in this post.
There are many others … several of which are mentioned in various threads on this forum … but there are very few with the same combination of reputation, experience, knowledge, materials, service, and value as these.
A few of these “others” (outside of the members here) that you may come across include …
https://www.foamsweetfoam.com/home (They are now a member here)
https://www.foamorder.com/
http://perfectlatexmattress.com/
Home | FoamSource
http://www.savvyrest.com/
http://www.purerest.com/
http://www.thenaturalsleepstore.com/
http://palmettomattress.com/index.php/default/
http://www.astrabeds.com/ and http://www.simplyrest.com/latex_mattresses (same company)
http://www.plushbeds.com/
http://www.absolutecomfortonsale.com/
There are dozens more that offer various combinations of custom choices and differing components or types of latex and exchange policies but this will give you a good idea. Some are more reliable than others or may have better value or options available.
While a local factory direct outlet where you can actually test the mattress you are purchasing is usually the best combination of quality and value, it’s nice to know that there are online options available for those that don’t have one of these nearby.
Phoenix