Hi sparkleman,
It would probably be beyond anyone’s ability to keep a list or keep up to date with the details of every mattress on the floor of all the retailers and manufacturers that are listed here so unfortunately I can’t answer your question specifically.
There are really only 3 ways to “match” another mattress which are discussed in post #2 here. As you can see … matching the “feel” of another mattress (based on personal opinion and subjective assessments) and matching the specs of a mattress (in terms of quality) or matching both at the same time where most people would agree that the “feel” is close and the specs can be shown to be very close can all be very different things. Many different types of layering and designs can have a very similar "feel"but this would have nothing to do with the quality of the materials that were used to achieve the feel.
What I would suggest is to do some initial work on the phone and call each retailer or manufacturer you are considering and ask them if they carry any mattresses that have a similar construction, quality, and feel to the Tempurpedic model you are most interested in and then visit the ones that seem to carry what you are looking for. There are many similar mattresses in terms of both feel, design, and quality of materials that would have better value (and because “feel” can be very subjective and vary with different people’s body type, sleeping style, and perceptions … different people would often have very different ideas of which mattresses “feel” the same.)
There is no way you would have to spend $4500 to have a similar quality mattress with similar feel, quality, and performance though. It just takes some “at home” research and detective work to track them down if that is your “target” 
Phoenix