Hi wavyphotons,
Thanks for the kind comments … and welcome to the forum 
The better options or possibilities I’m aware of in the San Fransisco/Oakland/Berkeley areas (subject to the “value” guidelines here) are listed in post #2 here.
There is more about adjustable beds in post #3 here and the adjustable bed topic that it links to that also includes some retailers that you can use as good sources of information and as pricing references that can help you make the most suitable choice. I don’t know of any adjustable beds that are made in a “non split” king size since they would be impossible to fit into most bedrooms and would be too heavy to handle. There was at least one manufacturer I know of that used to make one years ago (Electropedic) but they no longer do and it didn’t have any of the more modern features (such as a wall hugger feature) and was very very heavy.
There is more about the different ways to choose a mattress (online or locally) in post #2 here that can help you reduce the risks involved in each of them but only you can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved for anyone to be able to predict which mattress or combination of materials will be the best match for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) based on either specs (yours or a mattress) or theory at a distance (see mattress firmness/comfort levels in post #2 here). I would also keep in mind that there are no standardized definitions of firmness ratings between different manufacturers and that firmness/softness is also relative to the perceptions of different people and a mattress that feels too firm for one person can feel too soft for someone else so the only reliable way to know what feels firm or soft for you will be based on your own personal experience.
If you find out the “quality specs” of any mattress that you are considering (see here) and use the guidelines that it links to here (relative to your body type) then if a mattress you choose is a good match for you in terms of PPP (and not on the edge of being too soft) then it would certainly be realistic to expect a comfort life of 10 years.
Post #2 here from earlier today as well as post #3 here has more information about the same three mattresses and how they compare that may be helpful in understanding the differences between them.
You won’t “need” a bedframe with an adjustable bed (the adjustable bed would replace a bedframe and a foundation under a mattress) and you can just attach a headboard to the adjustable bed if you prefer one but if you plan to purchase a bedframe anyway and place the adjustable bed inside the bedframe then the bedframe would be strictly a preference choice based on aesthetics and would be more of a furniture item that isn’t my area of expertise (or an area where I do any significant research).
Phoenix