Derek, the Montbell pillow is really a cool pillow, one that is to me so comfortable to my face, I don't need a cover for it. It is 2.4 oz and per the web page is 3.9" tall (seems taller to me from memory but I have not measured it). I do know it is plenty high for me when it is appended (via the toggle switches) to the montbell 1" pad, making a 5' pad about 5'10.6" long sleeping setup (longer than the 5.5" NeoAir Medium pad I have). With the NeoAir, it is only comfortable if laying on top of the NeoAir, making a toggle arrangement difficult to work, except as a flip-back arrangement.
http://www.montbell.us/products/disp.php?cat_id=33&p_id=1124290
The pillow is spacious: Size: 10.6" x 18.5" x 3.9" for only 2.4 oz.
At this point in time, I am inclined to take back the NeoAir. I was able to affix the pillow to the NeoAir with bungie cord (all cord, no metal ends) but the weight equaled the offset difference between the NeoAir and the Montbell.
Like I said, I like sleeping on a firm mattress and the Montbell seems to mimic my bed better than the NeoAir.
The whole idea of the pillow being affixed to the bed seems foreign to many, but think of it this way, on your bed at home, nobody likes their pillow falling on the floor. The toggle system keeps that same paradigm on the trail. With the NeoAir, one feels like their pillow has fallen on the floor all the time.