I have been wrestling with this problem for a while now. I used to carry an ALPS camp chair that weighed ~22 oz. I really did love the luxury of it, and was the envy of my fellow hikers sitting on rocks, logs, etc. I ditched it last fall in hopes of shedding all that weight, but I have found myself bringing it again. I guess it's just a luxury I'm not willing to give up.
It seems like a great project for TiGoat or one of the other cottages to try and tackle. I would guess that by using some carbon fiber stays, lightweight fabric (cuben, with maybe a heavier-weight material on the bottom, evazote foam, and some light webbing, they could come up with something in the sub-10oz range. That would be worth quite a bit to me!