On my 9 day hike last year I did not get as good a sleep as I would like. The problem with a 4' sleeping pad is that to be comfortable, your head is typically on a pillow in front of the pad. An extra 8" of length would really be nice. I have considered the Woman's Prolite 4 Regular which is 5'6" long but it weighs 24 oz. The closest I could come to this comfort, after evaluating a slew of alternatives is this:
http://www.texsport.net/dual-foam-sleeping-p-158.html
A cut-down to 58" long Texsport Dual-Foam Sleeping Pad (1.25" thick of foam) plus two Office Max Bubble Wrap Protective Packaging Wraps cut down to 20" by 36 feet (folded in 58" segments. This amounts to 2" of cushioning, and it does take a lot of space, but the plastic Package acts as a waterproof wrapping for the Dual Foam pad too. With Rubber straps, the entire thing weighs 18.4 oz, which is 6 oz less than the Thermarest alternative.
I could get by with just one bag, but I wanted the two setups to be 100% equally as cushionable, and it took two Bubble Wrap packages to get it to that identical level of cushioning.
I'm wondering if anyone else has come up with something as comfortable as a 1.5" Prolite 4 pad that weighs less than one pound and is at least 54-58" long.
I have tried the Walmart Closed Cell Foam pad, the REI Closed Cell foam Pad, the ZLite pad, the Gossamer Gear 1/8" thin pad, and nothing came identical to the cushioning of a Prolite 4 pad as did the above combination.
Yes, it is bulky, but I am going to be using a LuxuryLite external frame this year, and it is easy to strap this 18 oz sleeping pad to the top of the LuxuryLite frame.
I wish Thermarest would create a 58" long Prolite 4 pad — I hate the huge gap between 48" and 72" (Yes, the woman's is only 66" but it weighs the same as the man's 72" pad).

