I've gone through the same dilemma when hiking the 46 Adirondack high peaks, but with the Golite Gust, which of course does not have the compactor things. I then developed a 2 oz daypack (basically a silnylon stuff sack with a single shoulderstrap and a waterbottle holder) the single strap carry is nice since it allows most of my back to breath, since it isn't covered by a pack. The pack holds about 1200-1500 cubic inches, which is just right for a long day hike. The over the shoulder concept allows fast access to the pack while hiking, and when going under blowdown, just swing it in front! when one shoulder gets tired, switch shoulders! When in my Golite Gust, or Cilogear 60L it goes on top and holds all the normal dayhike stuff for quick access, so the weight is never wasted, even on the approach. the 2 oz version is 1.1 oz silnylon with a waterbottle holder and a fixed length 1.5" grosgrain strap. with cuben fiber, the pack could weight next to nothing. You could tell people, "my daypack weights less than one of your socks!
durability is surprisingly good. My first silnylon version is patched across the bottom and doing fine, after well over a month in the Adirondack High Peaks and carrying climbing gear around.
If there is interest I could post a pattern and some pictures