at scouts recently we hit on an idea to lighten any load considerably. attach helium filled baloons to the backpack, untill the upwards pull cancels out the weight. then carry your weightless bag wherever you like.
we quickly spotted several major flaws in the plan, but would still love to try it.
a slightly more serious Idea was stashing gear at the place we regulaly camp, as we where there two weekends in a row. again never happened, as there was so little gear to stash, but it could be a consideration if you regualy camp in the same spot. (maybe some kind of buried cache or something?)