UPDATE!
1. The Storage System - worked like a charm for UPOverland 2009. Kept everything in place, and made it SO much easier to set up and break down camp in the pouring rain because there was no need to remove everything to get to the bottom layer.. ActionPackers on the bottom accessed through the tailgate, big totes and cooler on top accessed through the windows (rear and side), and a couple duffels and camp chairs on top of that. We were able to carry enough gear (minus gas and water, though we easily could have carried more water than we did) for two people/8-10 days.
2. Airbags - $86 well spent. Very well spent. I've been running 7-8lbs on the street, and 12lbs on the trail with a week's worth of gear. Upped it to 15lbs on a stretch of nasty corrugated sand where the peaks were slightly further apart than the Jeep's wheelbase. They handled the UP trip with grace, and handled the load in the back very well. Flexibility and articulation were only slightly diminished from the original setup, but it was a very worthwhile tradeoff for my uses. Are they as good as properly rated springs? Probably not, but for the price...