doing this for entire "real" addons seems kind of crazy. so much data to transmit. why not write an .exe (or java) updater than parses a savedvariables file? your raid leader says "yo, grab these addons" and everybody gets the list (including where they came from). they log-out, run the updater, then log back in. done. if they can't manage that, then raiding is going to be tough.