Hi, I'm looking for a really light, foldable back pack for macbook retina 15 inch. Is there anything available ? I've seen the Deuter speed lite 20 , and it's really something I like but I don't know if it would fit a 15 inch macbook retina. Anyone with this back pack know if macbook retina 15 inch fits or not ? If not, than any other suggestions ? Looking for a really light foldable backpack, preferably under 1 pound and can be tucked into a suitcase.