I picked up a Zrest off freecycle. It's the long length, regular width, 20x72. Weighs 15 oz. Potential uses:
Cut in half and attached together on the long side to make a short, double wide pad, 40x36. Haven't done this yet cuz I haven't figured out yet how I want to do the connection. Maybe overlap one row of eggcrate and cut small slits to be threaded with omnitape. Should be able to be taken apart for two half pads (20x36) to be used singly or stacked, or reconnected longways to make the full size pad again.
The full length pad only unfolded halfway with the unfolded half at one end makes a perfect height pillow. Obviously this wouldn't do if you like a fluffy pillow, but I'm a side sleeper and need a rather high, firm pillow. Taking just half the pad is still 7.5 oz. But cutting the width in half to 10" makes it 3.25 oz, comparable to the popular Montbell (regular, red cover) pillow in size medium (3.5 oz).
other pillow musings
I have the Montbell pillow and don't care for it as a pillow. It's currently being used as a booster seat in my packraft. Partially deflating it and wrapping it with my fleece vest makes it acceptable as a pillow, but the Zrest stack felt immediately more comfortable. For hammock camping, I use a MYOG pillow, 2" open cell foam with a jersey cover, (3 oz) but even doubled over, this is too compressible and doesn't provide enough height for ground sleeping. Given the comfort of the Zrest "pillow", I'm wondering if any closed cell foam block would do. Bulky, but comparable in weight to air pillows of similar size.