Hi Martin,
The better options or possibilities I’m aware of in and around the Greater Los Angeles area (subject to making sure that any mattress you are considering meets the quality/value guidelines here) are listed in post #2 here.
I don’t keep a record of the individual mattresses that the retailers and manufacturers in the hundreds of forum lists throughout the forum carry on their floor (it would be a bigger job than anyone could keep up with in a constantly changing market) but checking their websites and making some preliminary phone calls to the retailers/manufacturers that are on the forum lists that are in reasonable driving distance is always a good idea before you visit any store anyway. This will tell you which of them carry mattresses that would meet your specific criteria, are transparent about the quality and durability of the materials in their mattresses (see this article), and that carry the type of mattresses that you are interested in testing in the budget range you are comfortable with and that have exchange or return policies that you are comfortable with. Once you have checked their websites and/or talked with the ones that interest you then you will be in a much better position to decide on the ones that you are most interested in visiting based on the results of your preliminary research and conversations.
Innerspring mattresses in general are a very broad category and since they are the most common type of mattress in the industry (see this article) … there would be hundreds if not thousands of innerspring mattresses available in the stores in the area.
Phoenix