Hi Pixbroker,
While this is a memory foam mattress … it wouldn’t be the same as the Tempurpedic you had if it only has 2" of memory foam because the Tempurpedic you had would have had a thicker layer of memory foam and may have been denser or “more supportive” memory foam as well. Since the mattress you have only has 2" of memory foam the issue could be that there is a fairly low quality foam underneath the memory foam that has softened which along with the changing response of the memory foam with temperature and time may be aggravating the problem. The issue of memory foam continuing to soften over the course of the night and allowing you to sink in more deeply over time and with changing temperature is a common issue with memory foam mattresses and one solution is to use thinner layers of memory foam over a more resilient layer that isn’t temperature sensitive but in your case you appear to already have a mattress with a thin layer of memory foam so there may be more happening than just the softening of the memory foam. Do you happen to know more specifics about your mattress or the densities of the foam layers (either the memory foam or the polyfoam underneath it).
The key here would be to identify why your symptoms are happening but dn’s suggestions would be well worth trying. If the main reason for your “out of alignment” condition when you’ve been sleeping for a while is the softening of the foam underneath the memory foam then you may need to replace the mattress.
While it may not help with your current mattress … it may be worth considering memory foam that is less temperature sensitive and changes it’s response less with temperature. Many of the gel memory foams and some of the newer memory foams are less temperature sensitive (they have a smaller range between “firm and mushy”). If you also have a mattress with only 2" of memory foam in the top layer then the quality and properties of the foam underneath it would be a significant part of both the feel and response of the mattress and its durability as well.
The adjustable slat system may be a partial solution (firming up the middle part of the slats under the pelvis) and may be helpful in combination with other ideas such as dn’s suggestions even if any one adjustment doesn’t work well enough by itself.
Tall and thin people usually fall on one of two ends of the spectrum. They either need softer comfort layers than normal because their lighter weights need softer foam to sink in more and relieve pressure or they need firmer (or sometimes thinner) comfort layers than normal so that they have “just enough” pressure relief but still have freedom of movement on the mattress. Many tall thin people tend to be “sprawlers” and don’t like or do well with sinking in too far into their mattress. They may also be more sensitive to pressure points (their bony protrusions such as shoulders and hips can be more sensitive) and also to alignment issues because they may have higher weight concentrations in the middle of their body. Your own experience will tell you where on the spectrum you may be.
I’m assuming you mean “latex” rather than “latest”? If that’s the case then most European flexible slat systems would be fine. In North America a latex mattress usually (but not always) uses a firm non flexing support system so a flexible slat system would become an “active” part of your sleeping system and may change how the mattress feels and responds compared to what you test in a showroom if it has a rigid support system. The slats will have a bigger effect with thinner latex mattresses than they will with a thicker one. Although a rigid support system with a thicker mattress where the mattress itself does all the work with its support and comfort layers is more common here … there are also some manufacturers who sell thinner latex mattresses that are designed to be used on either an active box spring or a flexible slat system (either tension adjustable or not) as part of the sleeping system.
Many factory direct manufacturers either local or online can build a mattress to any size you wish as a custom order. The tutorial post here includes a link to a list of the members here that sell latex mattresses online in many different designs and price ranges and many of these will build a custom size. The tutorial post also has the basic information, steps, and guidelines that can help you make the best possible choices.
Some of the better options I’m aware of in the Las Vegas area are listed in post #2 here but there are no factory direct manufacturers in the area that make memory foam mattresses so I would call them first to make sure any of them are able to order a mattress that works well for you in a custom size from their supplier.
A forum search on Plushbeds (you can just click this) will bring up more information and feedback about them.
What I would probably suggest is a thinner layer (probably in the range of about 2" or possibly even less depending on your testing and experience) of firmer less temperature sensitive memory foam with at least 4 lb density )so that when it warms up more you don’t keep sinking in quite as far) with a more resilient layer underneath it that isn’t temperature sensitive and is a good match for you in terms of PPP. It should also be a very high quality material so it will be more durable and not soften or break down too quickly. Latex would be a good choice here. Of course you could also buy a latex mattress that is “on the firm side” and then add a 2" memory foam topper. All memory foam will be temperature sensitive but there is a range of different temperature response between different types of memory foam (you can see some of the different properties of different types of memory foam in post #9 here). It may be worth trying one of the Tempurpedic weightless collection as a reference point which use a thinner memory foam layer over a more resilient polyfoam underneath it (instead of thicker layers of memory foam) as an example of this general style of mattress although there would be others as well that have a different feel and performance in the same general style that would be in much lower price ranges.
Hope this helps to give you some sense of direction.
Phoenix