A friend of mine was telling me that he wanted a cooler that would hold a couple of cokes and fit in his Motorcycle Saddle Bag. Since I had some 1 inch foam left over from my build, I thought I'd give it a try. I asked him for the inside dimensions of his saddle bag and he said it was the size of the old 12 packs.
So with a few drink cans as a template, I started to construct a foam cooler for a saddle bag. I glued it using the Blue can of Great Stuff then sealed the corners with silicone caulk. There is an extra 1/2 inch of insulation on the bottom because of the exhaust pipes being right under the bag. Also there is another 1/2 inch of foam on the lid with door insulation around that for the seal. Then I glued on T-shirt material for a cover. It isn't very pretty, but MAN! It holds the ice better than most store bought coolers. I filled it with Ice and left it in my hot car, in the sun, for 5 hours. I lost less than an inch of ice and only a cup of water poured out.
The best part was the cost. Free, because it was all scrap materials.
Dave
It isn't quit finished but it does work well. It's supposed to look like a coffee cup, though I believe a LOT of people will see a beer mug. 
