Yeah, I did one for my Dactyl Manuform and just oversized it by a couple millimeters and stuck Amazon bubbly envelopes on the inside. The bottom of each half is flat, the same shape, and rubberized, so the covers just go over the top, I clap the bottoms together (tee hee?), and chunk the whole thing in a lunch bag that barely fits. It stays together without slipping and without any attachment between the two cover halves. Janky but it's worked for years.