a cozy is a neat idea, but wouldn't wrapping the bars (in a ziplock bag of course) in a pullover or some other article of clothing (I have used a pair of clean socks with success) stuffed deep into the nether regions of the pack work as well, at less weight?
I use clothing to insulate pots as well.... Even though reflectix is light, it is still another "thing" to ahve to deal with.
I've used the sock or pullover (Mt Hardwear lightweight windshirt) technique with success with Smoked salmon, cream cheese, cheddar and chocolate bars on trips into several days. This summer will be the first time I use it on a weeklong, but by the last couple days all the "cool" stuff will be gone or ensconced in a cold stream anyway.
I know this is probably not news to you folks, so Sarah, what are the benefits of the cozy I've overlooked, as far as keeping stuff cool is concerned?