Hi Jester,
Flexus has several lines of innerspring mattresses that may be well worth trying but I don’t recommend specific mattresses because only your own careful testing for PPP can tell which mattress design is best for you (see mattress firmness/comfort levels in post #2 here). I also don’t keep a record of individual mattresses at all the stores that are listed in the forum (which would be an impossible job to keep up with). There are even more options with innersprings than there are with latex mattresses and some of them may work very well for you and others may not be suitable at all depending on your body type, sleeping positions, and personal preferences and circumstances.
The steps in the tutorial post here will help you find the mattress (innerspring or otherwise) that is the best match for you.
Phoenix