I will be watching this thread intently. I too am concerned about weight issues with DS's BOB. We assembled the items, as detailed in wildman's thread over here

http://forums.equipped.org/ubbthreads.php?ubb=showflat&Number=192002#Post192002

and lo and behold ... it's too heavy for DS, almost too heavy for me. And it's not even complete yet. Still a lot of components missing. So time to reevaluate and start shaving some pounds here and there. On the BOB, not me.
Unfortunately 777, cutting weight usually costs $$$$. Any budget-minded alternatives would be greatly appreciated for both of us. And DS too.