The 6000 Review is up as well:
http://kuiu.wordpress.com/2011/02/01/icon-6000-review/ The Icon frame allows this pack to be incredibly comfortable to hunt in all day due to the horizontal flexion. The vertical stiffness of the frame and the stays designed to decouple a heavy load, moving the weight off of your hip bones and shoulders and to your lower back, upper back and chest make these packs the most comfortable pack on the market.
I might be missing something here, but I recall reading about Kifaru, Mystery Ranch and McHale that their load distributions moved weight to your hips to bear a good part of the weight. Lowering the center of gravity of the pack making it more comfortable for heavy loads. Just thinking out loud, but it seems that your lower back is the last place you would want bearing your pack weight.
