We recently finished a set of custom sling bags for Elle at Tiny Helmets Big Bikes. We used 1000 denier cordura, nylon webbing, and nylon binding tape on these. An illuminite reflective panel was added for night time visibility. The end panels are mesh with a drawcord to keep loose items under control. Inside is a full length packcloth lined pocket featuring a waterproof zipper, and drain holes in the bottom of the bag. We designed these bags specifically for the Yuba Mundo, no retrofitting of other cargo bike slings needed. We may offer these in our store at some point but for now if you are interested in getting a set, drop us an email and we can discuss a custom set.