Doesn't the AirX have the carbon/delrin loop too? Maybe it doesn't....I'm too lazy to go look at the website again. This would help explain the load rating.
The Exodus FS pad looks like a good size for a pillow, but I think a bit more innovation is required before this pad would really fall into the 'awesome pillow' category. It's nice and big, but it's just an inflatable and that never feels that great. You'd still need to pile ample clothes on top to make it nice. What I would like to see (just thinking as I type) is a pad/pillow that inflates with air to a high PSI for use as pack frame, but then it's also filled with soft foam for use uninflated as a pillow (ie. the foam would provide the head support, so you could leave the valve open during pillow usage).
There is a bit of a fundamental problem with the pack frame/pillow idea and that's the thickness. When used a packframe you want the pad fairly thin, so your load is carried as close to the back as possible, but when you're using it as a pillow you really want it thicker than 1.5" or so. Something like 3" thick of soft foam would be awesome. To really accomplish this you'd need to do something like dual compartments, which would likely get complicated, heavy and expensive pretty quick.