S.W.
All natural latex foam may be what you are looking for. It is not cheap. It is hypo allergenic. It is made in Canada and Europe but as far as I know not readily in the US.
Still, 10 years ago when we needed a new mattress I learned that European Sleepworks was a store that sold what I was looking for. They are located at 2966 Adeline Street in Berkeley [###-###-####] and you can check them out online at www.sleepworks.com/ . They sell latex mattresses and mattresses with latex and coils. We have a platform bed so we didn't purchase the box.
Like all mattresses you need to go to the store and check it out before deciding on the one for you - especially when you consider that 1/3 of your life is spent sleeping and that a good mattress lasts 15-20 years.
Good luck and happy snoozing.