If you have a local hobby shop that orders from SIG and they get the 48" balsa in, ask them for some of the boxes that their shipments come in. Balsa is best stored flat. if you have any kind of shelving in your shop, reserve the top shelf for balsa. Lay a 48" long piece of plywood down first, then stack the wood. Old school balsa racks from hobby shops were square pigeon holes for each size, but that takes up room. If it is just for storage until a later date or for a move, get some 48" long boxes, even if you have to buy them new. Check your local U-Haul store, and flower shops get their flower stock in long boxes.
just think out side the box (sorry!) and you'l figger it out!
Dan McEntee