Roller crimping -- I've seen that technique before and have been wondering how that could be scaled down. I was thinking modified turf rollers that a person could push around, but I've no idea how that could be done easily
Charlie, do you live anywhere near colleges and universities? This time of the year, thousands of new and returning students bring their stuff in basically plain cardbord shipping boxes. Sometimes they buy new ones at U haul and mailbox stores. I wonder what they do with them all after the students all move in?
If you don't need the cardboard to break down any time soon, appliance boxes are triple- and sometimes quadruple- layered. The installers take them back with them for you but they must take them somewhere.
ETA -- Ah, there you go! Eric has the answers.