Ha! I didn't catch the scent of sarcasm, Franco.
I had read your post but I was still being serious about the stuff sack. A pillow cover and a stuff sack aren't quite the same thing, right? One has the ability to cinch closed tightly making it easier to keep the contents somewhat contained/compressed.
In any case (given how much time you've spent on the issue of pillows) you clearly didn't need any suggestion from me!