Just a thought on the cooling side of things, anyone ever tried packing in a bit(very, very little mind you) of dry ice in there with that insulation? It wouldn't get soggy and so long as your box isn't airtight it wouldn't be likely to have pressure issues. I'd just be sure to give the stuff it's own space and not touching the bottles since it could very well freeze things or at the very least make the glass more likely to break. Though I've no idea on the legality of it but can't see it being much of an issue and it could do wonders for keeping brew cold on hot days.
Primary 5 Gallon - Ode to Arthur Stout
Test Gallon 1 - Fiery Ginger Beer
Test Gallon 2 & 3 - Empty
In Bottle: Cincinnati Pale Ale, Coopers English Bitter, Brewmaster Cider Kit, Hard Cider testers, Blackout Ale