I have a pair of Roll-A-Cots which I've used for several years. They weigh 10 lbs. each for the standard size; they have a wider version (same weight) and a wider/longer version (13 lbs.). The tension of the sleeping surface is adjustable. With a Thermarest mattress on top, they are easily as comfortable as our Select Comfort bed at home. They sit high enough to comfortably sit on. $130 on Amazon. Their website is pretty descriptive: http://www.camptime.com/roll-a-cot.htm
With the Thermarest insulating me, I don't think it's any colder than if I were on the ground, at least not enough to complain about. I guess the coldest I've slept on them is about freezing at Marble a couple of nights. It is nice to be able to store stuff under them, and to have someplace to sit in the tent besides the floor.
You'll see a lot of favorable comments about these cots, and I've sure been pleased.
Cary