Chips, with your 15inch MBP stuffed in there how many additional things do you think you could carry? I'm contemplating a 257, but am also considering a 258. Ideally, I'd love to be able to fit my 15" MBP and an overnight set of clothes if possible. Talking undershirt, shirt, pants, socks, etc. A toothbrush, contact case/glasses and all that would be nice as well. Think it's possible? Looking for a daily bag that can also double as an overnight bag if necessary.