Well, no thanks to Steve (everyone say it, now--Thanks, Steve!) my brand new NeoAir just went under the knife. What sleeping pad have legions of people asked for, and yet no manufacturer makes? You guessed it... a wide but short pad.
That said, my approach with the mini-project was that I wouldn't choose a wide pad if I were really, really counting grams. I chose a wider pad because I want more comfort. So in terms of length I made a compromise, ending up with a finished length of 59 inches.
Yup, that's right. A large NeoAir (stock 25 x 77 inches, 18.8 ounces) cut down to 25 x 59 inches, resulting in a finished weight of 14.25 ounces. And that's not all! Gotta say, blowing up that huge ol' mattress wasn't fun. Goes easier now that there isn't so much volume.
Incidentally, I noticed that the pad partially inflated itself while I had it spread on the counter prior to resealing. It only took a few (ten??) more breaths to fully inflate it later. The directions do specify to leave the valve open if you leave the pad in your tent for the day; not sure if the inflation I experienced was because of the sunlight and warmth in the kitchen, or just because the material inside the pad expanded a bit.
Anyhoozit, thought you should all know it's been done and possible. It was an extraordinarily matter-of-fact experience. After making your initial cut, I would cut across the pad one layer at a time, because otherwise you'll get a bit of a curve cut into your lower layer. No worries. The material seemed to get the best seal with my iron set on high. The only moment of true excitement was when one of my Shepherd mixes decided to walk on the pad just after I pulled it off the ironing board and inflated it.
I did try the pad maybe twenty minutes after sealing, seems fine. Headed out for two weeks starting this weekend, so I hope the bond holds!