Hi Sonic,
Good advice and I couldn’t agree more about the need to completely relax on a mattress to test for pressure relief.
Hi Sleepless in wi,
We have two sleeplesses now so I have to add the area as well 
The orthogel uses what is called bucking column gel and it’s a very durable material and will last for a long time. It has a unique way of relieving pressure because the columns which are under pressure will collapse while the rest which have less pressure will stay more stiff and continue to hold weight. It can be a very effective pressure relieving material although it has an unusual feel to it when you move and the columns buckle. 1" of quilting polyfoam is thin enough that it would also not be a durability issue and with buckling column gel its a good idea to have some foam on top for a more consistent feel. The Acella-Flex foam usually comes in 2.0 lbs and is a good quality support foam. the only down side to buckling column gel is that it’s an expensive material (even more than latex).
There are also other versions of this material including intelligel which use a different cell structure and use a heavier more pure gel rather than the foamed gel used by Natura and are a little less stiff. Serta used intelligel in several of their mattresses including this one which had 2.5" of the intelligel and had 2" of Talalay latex over it along with a 6" soy polyfoam core.
Both of these are buckling column gels are licensed from Edizone.
Beloit Mattress Company in Beloit, WI or Rockford, IL would be well worth the trip to go there. They are a member of this site which means that I believe they compete well with the best in the country and are also great people to deal with. They have a wide range of mattresses that include gel memory foam, memory foam, latex, and innersprings.
Verlo Has stores in Madison, Janesville, and Fort Atkinson (among others in WI and Northeast IL) and is a regional factory direct manufacturer and has a wide range of mattresses of many types (innerspring, memory foam, latex etc). They also do custom work and can adjust their mattresses to suit an individual. Note: their store in Madison is small and doesn’t carry their full line (see post #4 here).
Denver Mattress is another regional factory direct manufacturer with stores in Madison, Wi and Rockford, IL (among others). They also make a range of mattresses including innersprings and their iChoice which is a mostly latex mattress that has the option of a memory foam or latex comfort layer. They may also be well worth visiting.
http://www.satarahome.com/ Retailer in Madison that carries Savvy Rest (including their component latex mattresses), Sleeptek, Suite Sleep, Royal-Pedic, and Naturepedic. They are all very high quality mattresses but I would also make some careful value comparisons because they tend to be in a more premium price range.
I don’t think you will need much more in the way of options as these represent some good value and/or selection.
Phoenix