Hi dnazarian,
The uppermost layers of a mattress will have the most dramatic impact upon your comfort, and as memory foam has a very unique feel (viscous and elastic properties), to achieve a “memory foam feel” you would probably be best suited with a memory foam or slow recovery latex topper.
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 specific criteria and the quality/value guidelines here, some options or possibilities I’m aware of in and around the San Francisco/San Rafael/Oakland/Berkeley areas are listed in post #2 here. Site members located “close” to you are FloBeds in Fort Bragg, Nest Bedding in San Francisco, and Bay Bed and Mattress in Santa Cruz.
Phoenix