After receiving no responses to my Neoair All Season question, I decided to go ahead and just cut it down and seal it back up like the original Neoair.
What happened? Well, it went back together flawlessly. On the inside there is a mylar layer attached to the inside of each top and bottom piece of fabric. Within each baffle is two layers of the white, dryer sheet looking material as well as a layer of the mylar. I simply cut the insulation back, and ran my household iron over the two layers of fabric a few times. Being careful not to leave any air bubbles. So far, so good. I left it inflated with weights placed on top overnight, it didn't deflate at all.
Original weight was 26oz, and after the modification is 22.3oz. Not a bad little reduction for about 10" cut off the bottom.
I will post pics of the inside of the pad for anyone who is interested. It won't be until later though.