I've been doing this with my GoLite Peak. It's heavier than most of the packs here, but for your uses that isn't such a big deal. I leave out some bits- the foam pad in the back and hipbelt padding/pockets, which are worthless for weight transfer- and pack the bag into the zippered pocket. Roll it up and put a rubberband or some cord around it and it's a small loaf of bread, maybe 20 oz. Bigger than what you're looking for, but the compression system is pretty nice, made of Dyneema, somewhat ventilated, and comfy for folks with longer torsos.
I've considered the Mountain Hardwear Scrambler and Montbell Versalite, but never seen them in person. Look like OK options, though.