Hi jammin,
There are several manufacturers on the Bay Area list in post #2 here which offer similar mattresses with a similar build and materials … some of them with good value as well. A few phone calls asking about a “latex polyfoam hybrid with several inches of latex over a polyfoam base” will find a few that would be worth visiting. While these will not be exactly the same… they would at least give you a good sense of the overall feel of a latex/polyfoam hybrid even if the softness/firmness or some of the layering may be a bit different.
Hope this helps.
Phoenix