Hi SDsleeper,
The better options I’m aware of in and around San Diego are listed in post #2 here.
What I would suggest is calling these and asking them if they have a “latex hybrid” mattress with about 3" of latex over polyfoam.
This will help you find the best local value for this type of mattress although they may not be in the same range as the Dreamfoam (which has much better value than most mattresses of this type).
The iComfort insight is made of a slow response foam (gel memory foam is similar to regular memory foam) and the Ultimate Dreams has a similar construction except it has latex which is a fast response material in the comfort layers. While both types of mattress can provide the pressure relief and support that are needed (depending on how well the layering matches the needs of the person) the materials that are used to provide these will feel very different.
Being a primary stomach sleeper … you will likely need a thinner and firmer comfort layer than someone who was primarily a back or side sleeper to offset the risk of sleeping in a swayback position on your stomach. Most stomach sleepers also sleep in other positions though for a significant part of the night so I would choose the thinnest and/or firmest comfort layer that provides you with the pressure relief you need in your other sleeping positions which will generally allow for the best alignment when you are on your stomach.
Phoenix