This might be an option for your closet.
http://www.slidingdoorco.com/

Thanks for the web link, but I am trying to avoid anything that takes up wall space outside the closet, and yet provides the widest possible opening for the closet. Hence the interest in a 'roll up'/retractable screen door. Part of my problem is that the bedroom door opens to block part of the closet, so I have to watch what it would 'bang into' if opened abruptly