This may work in other SUV’s, it depends on how well it sits flat. The beauty of an Xterra is that its designed to be completely flat.
We used to just have a pile of Sleeping bags and blankets in the back of the Xterra, and it was ok, quite comfortable, but not as comfortable as home, especially on cold nights when more of the cushioning ends up on top of you
So we Carpeted it completely, twice, and its now just really super comfortable
Here’s what we did:
We found the thickest softest carpet we could find.
We got enough carpet to do the entire Xterra twice
We cut it around all the corners and little cargo spots under the nets etc, very carefully
We Cut it just up to where the top of the rear seats fold down, and a few inches beyond
We did that twice, and we set one layer of the soft carpet on top of the other layer, for a double-layer of carpet.
We then cut separate Panels that slide between the two layers of carpet, and then pull out to sit on top of the two Action Packers, which make a level bed, or two coolers, which is only about an inch taller. The carpet smooths out the transition nicely and the bed feels completely smooth.
So you slide your seats forward, lower the coolers into the well behind the seats, and then these carpeted panels just slide out and cover everything, making the entire thing carpeted & extra comfy.
After the carpeted panels are pulled out as far as they can go against the front seats, the panels are still several inches under the carpet.
The Double-carpeting added a good degree of insulation as well
The reason we didn’t use Carpet Foam is that it breaks down and can ruin under-lying layers. and cause permanent damage.
So that’s how we’ve made our X go from pretty comfortable, to home-quality comfort.