Just found this on the intertubes tonight: http://mattresslogix.com/home.html

They make *custom* mattresses using springs, but they customize the springs based on your body size/shape.  Then they top it all off with Celsion Latex or Memory Foam.  And, they come to your door with a truck with all their equipement. It looks like it's based in Texas but they say they will go anywhere... Prices are high but not unreasonable at all.

The website explains it better than I could - this page is probably most illustrative: http://mattresslogix.com/biomechanics.html

So this all sounds too good to be true - anyone have any experience with them? Or even second hand comments?

Their website says they even have a return policy, but that link didn't work... 

This looks like the ultimate solution.  Surely we have a Texan around who has some experience with Mattress Logix??????