Not sure exactly what CaT means by paper thin.
The thickness of the pad? Or the material it's made of?
The latest Neo Air from thermarest is very light and
pretty darn thick (9oz 2.5in thick)
Although it seems like it wouldn't hold up well...
I've been using one for a couple years now
(whenever they first came out with it) (2008?)
and it's still running strong after easily over 30 trips.
As for closed cell... my Z-Rest is easily 10 years old,
if not older... still works a treat ...
I prefer to sleep right on granite... so a air pad is a
welcome part of my kit.

Have fun