I was reading an old post on trampoline vented backpacks and it got me thinking. I have a Golite Gust pack which I find quite comfortable. My main problem with it is in warm weather my back is always saturated with sweat. In checking out some of the different venting options of commercial packs I came across an egg crate foam ventilation system used by REI:

This got me to thinking that I could make a similar style insert to use with my Gust in warmer weather. Has anyone tried this or have any comment before I go and spend time and money on the idea?