How good are you with wood? I took a sheet of 3/4 exterior plywood, ripped it down to just under 16 inches (3 lengths). Then used 2x3s as support for the plywood (box the plywood pannel). Then stacked the pannels so I could fit my boxes between the shelves and lag screw 2x3s on the ends as supports. Ended up with a 16 inch wide, roughly 5 ft tall, 8 ft long shelving unit. Also used a scrap piece of 1x2 as a diagonal brace to keep it from racking. Not sure if I have any pictures????