In the meantime, here's a look at my current prototype, in which I'm scribbling my thoughts on how it's shaping up:
This version is laser-cut and bound in folios with a Coptic binding; it has a hard cover and a magnet closure. It lies flat when opened to any page, which is an improvement over my previous binding. I especially like the way the hard cover encases and protects the delicate pages and exposed binding inside. I also like the laser-singed edges.