Hi Hardtimedeciding,
Not that I’m aware of … and it would probably take many months of intensive research to put together a list of all the thousands of mattress that contained some degree of 5 lb memory foam (with or without other types and densities and layer thicknesses of foam) and by the time it was complete it would probably be out of date.
Keep in mind that 4 lb memory foam is not a “bad” foam and many people prefer lower density memory foams because they tend to be less temperature sensitive, more responsive, breathable, and in some cases softer … they just tend to be less conforming and less durable. With higher weights it would be a good idea to consider mattresses that have thinner layers of 4 lb memory foam or other design factors that would reduce the risk of foam softening (such as higher density foam over the 4 lb memory foam). You can see some of the many factors that contribute to durability in post #4 here.
When you are making comparisons in the same foam category … higher density equals higher durability but there may be differences in the feel and performance of a lower density material that are worth the tradeoff. A mattress will also tend to soften and break down from the top down so the quality and durability of the upper layers is a more important part of the durability of the mattress than the deeper layers. The closer to the top of a mattress a foam is, the the more compression forces (that soften or break down the material) it will be exposed to.
Phoenix