Hi tsbuhr,
There have been a few changes in the Tempurpedic lineup since you purchased your DeluxeBed.
The old Tempurpedic DeluxeBed had the following layering …
1.2" TEMPUR Comfort Layer (5.3 lbs./ft. density) —Softer formula
2.8" TEMPUR Support Layer (5.3 lbs./ft. density)
Two Approx. 3" Airflow System Polyfoam Base Layers
The Contour Select which was introduced later had a very similar design …
1.2" 5.3 lb TEMPUR comfort layer
2.8" 5.3 lb TEMPUR support layer
6" Airflow Polyfoam Base layer - 2.2 lb density
… but as you discovered it was firmer (it was rated as a firm) than the DeluxeBed
The Contour Signature was slightly different and contained …
1.6" 5.3 lb TEMPUR comfort layer
2.4" 5.3 lb TEMPUR support layer
8" Dual-AirFlow System polyfoam base layer
… but was closer to the DeluxeBed in terms of its firmness level (medium firm)
None of these are currently being made any longer and none of their current mattresses have a similar design but the current mattress that would probably be the closest would be the Contour Elite which Tempurpedic rates as medium firm and contains …
1.2" Tempur HD 7.1 LB
2.3" Tempur Material 5.3 LB
Dual Airflow system
4.5" Airflow Polyfoam Base layer 2.0 LB
4.5" Airflow Polyfoam Base layer 2.0 LB
Comfort and softness can be somewhat subjective so not everyone will agree that one mattress is a good match for another one so I would suggest testing the Contour Elite in a store to confirm whether it feels similar to your DeluxeBed to you. The Tempurpedic Rhapsody Luxe may also be worth testing since Tempurpedic also rates this as a medium firm mattress. You could also test the rest of their current models to see if any of their other current models is the best match for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences)
If the Contour Elite (or the Rhapsody Luxe) feels similar to your mattress or if any of their other current models are a better match for you then the tutorial post includes this link to some of the better online memory foam options I’m aware of and several of them make mattresses that are designed to approximate the various Tempurpedic mattresses and if you talk with them on the phone they will be able to tell you which of their mattresses are closest to the Tempurpedic mattress that you are using as a reference point (whether it’s one of their past models such as the Contour Signature or one of the current Tempurpedic model lineup).
The Boston List includes quite a number of manufacturers or retailers that make or sell memory foam mattresses but you would need to test them in person to see which ones feel closest to the DeluxeBed to you. You could also call them to ask if any of their memory foam mattresses are similar to the current Tempurpedic mattress that you prefer.
Phoenix