Hi Postal007,
I can sympathize with your experiences and while they are unusual in the number of mattresses you have tried … your experiences themselves are not unusual at all. The major brands are just not the same quality as they were 10 or 15 years ago and there have been many changes in the industry including the ones that Sleep1 mentioned which together with not disclosing any meaningful information about the quality of the materials that are inside them are the main reasons I suggest avoiding them completely. To use an analogy … in most cases when you buy these mattresses you are paying real wood prices for a mattress that contains particle board … and they won’t provide you with the information that will let you know.
Unfortunately with these brands and manufacturers … the price you pay is not an indication of its quality, durability, or suitability.
As Sleepy1 mentioned … there are no shortcuts but there are steps and information that can help you break the cycle you are on. The first of these is to spend an hour or two reading post #1 here. this is the single most important post on the forum and the information and links that are in it will give you all the basic information you need to help you avoid the worst choices (like all the mattresses that you have tried so far or any other major brands or chain stores) and help you identify the better ones to focus on (usually smaller independent manufacturers that either sell factory direct or through better sleep shops that use much better quality of materials and lower prices in any apples to apples comparisons and have the knowledge and experience to help you make better choices).
In a word … no. It would only give you two variables to deal with. There are much better directions than trying to match a mattress to a topper and this would only be a good idea if you had no other options IMO.
This could definitely be a good possible solution but the layering of the foam above the innerspring will be very important (it’s the weak link of a mattress). Your own testing will help you decide if this is a good option and if it is the design and layering that is best for you but more important than that is to make sure that you are dealing with a retailer or manufacturer that will not only help you know the quality of the mattress you are buying but will help you make the most suitable choice.
This could also be a very good options and once again it would be well worthwhile testing different versions of latex or latex combinations (such as a latex/innerspring hybrid). Once again the guidance and knowledge of who you buy from can be more important than what you buy.
You are fortunate to live in the SF Bay area because you have some great choices available to you. I know you’ve seen this but for others who are reading this thread they are listed in post #2 here.
The first step is some reading. The next is knowing what to exclude. The next is to talk with each of the options in SF that attracts you and talk with them on the phone (before you go there). In other words decide on who you want to work with and who you best connect with. Tell them the short version of what you have written here or any part of it that you consider most important.
The next step is to visit the ones that you connect with and test mattresses with their help and guidance and narrow your selection down at each retailer or manufacturer you visit to one.
The final step … and by this time you will have “all good choices” is to use your own personal value equation to narrow your choices down to one. Knowing all the layers of each mattress you considering will also help you make “value comparisons” and your own personal value equation will help you make all the objective, subjective, an intangible tradeoffs that will help you narrow them down to one.
They carry OrganicPedic (OMI for short) which are high quality latex mattresses but much higher priced than other mattresses that use similar materials. They also carry Pure Latex Bliss which are also latex mattresses (they have a blended latex line and an all natural latex line) which are “better than average” value in many cases but also not in the same value range as many other choices you have in the area. They carry Technogel which are a specialty mattress that uses anywhere from 1/2" to 1" of “soft solid gel” (similar to some of the gel that is infused in memory foam and other materials but in “pure” form) but other than this they use materials that are commonly available in other mattresses and also carry a much higher price than the materials in them would normally justify. Finally they carry Tempurpedic which are mostly high quality (with some exceptions which use lower quality materials) but are also significantly overpriced. In other words … they tend to carry good quality mattresses at premium prices.
Hope this helps … and feel free to post with any other questions that can help you get off the merry go round of “bad” mattresses 
Phoenix