Polly, I really like your method of putting the cardboard thing between your stacks. It keeps everything in it's own pile. No falling over into the next pile. Although it doesn't take up much room at all, I had a brain storm of using coathanger wires cut to length and little holes drilled top and bottom to pop them into.
I have got to get my fabrics organized. It has gotten to the point where I can't be creative.