Interesting replies
My saddlebag is a Nelson Longflap. It's great for touring, but as it sticks out sideways it's not the best for off road. The buckles can be an issue, but if that's the case you could use the Camper C which has modern nylon closures. Also the cotton material is heavy. I'd love to see a lightweight version that uses modern materials with the design features of
the traditional saddlebag.
The Bagman is almost perfect, I just wish that they hadn't relied on a couple of set screws to hold it together. I would have threaded the ends of the rods that go into the mounting block, made the holes in the block thru-holes and held everything together with a washer and lock nut on the end of the threaded rods. Some versions of the Bagman seem to have issues coming loose so to avoid this I put locktite in the rod holes and on the set screws and it's been very solid.