If only to carry papers, why sides at all? I would consider a narrow base, maybe 1 inch? You know how much it needs to carry. Then 3 or 4 horizontal straps, ranging from maybe 3 inches at the bottom to maybe 8 inches at the top, you'll have to work out the lengths. Each strap sewn on one side and snaps on the other. Now you have something that can open like a briefcase to extract something quickly or undo the snaps to open completely. More versatile and less weight.