A few years ago I went through the same process as you. Back then, the memory foam (Tempur) mattresses were also pushed a lot onto the customers (and still are from what I can tell), but I hated them. Every time I lay onto one of those in the store, I felt like I was "dead weight" (I don't know how to describe it differently). I hated how my body sank into it, and I hated how it took a tremendous amount of effort to get out of one of those beds because the mattress would not bounce even the slightest bit. No way in hell I was going to buy one of those!

In the end we also settled for a latex mattress, because it breathes. It's soft, bouncy and very supportive for the back. My wife is a back patient and sleeps like a baby in this bed. I must say this mattress is easy twice the thickness a normal mattress is, but it's just sooooo good, I really don't care.

The brand I bought is Lattoflex, but I don't think they sell outside Europe. The site is also not in English, only Dutch and French, but with the help of Google translate it might still give you some ideas. I'm pretty sure a comparable product exists in America.

This is my matrress : click. I love this thing! I must say, it's also helped a lot by the pattented Winx bottom. In this movie clip, you can see how Winx works. In this movie clip, you can easily see how thick the mattress really is.