Lots of great ideas to consider... thanks! DS will be arriving in Paris early in the A.M. and will have to haul his gear around with him while touring. He'll be doing quite a bit of walking, getting on and off trains, etc. On weekend trips it will be much of the same thing. Consequently, he thought it would be easier to keep track of his stuff if it's able to be put together in one unit, rather than juggling multiple bags. (Think "Amazing Race" participants, if you've seen the show.
) I do like the idea of taking a collapsible duffle, and we have several, but I'll probably have to talk him into it. He's really trying to pack simply and lightly.