Instructables user kaymcleod has detailed the plans for a very rad round shoulder tote bag:

This is my latest and most frivolous sewing project. What use is a round bag, after all? Well, you can put things in it, and if necessary roll it down a hill. I had the idea for this bag months ago, but then got engrossed in other… well, less round projects. Now I’ve finally got around to it, and I’m delighted with it! Highly recommended for anyone who wants a round bag.