I've been wanting to try out a coptic binding one a book, as I think I want to include it in my Stitch and Surface class next semester as a project. So after cutting up a watercolor painting for another project this evening, I collected the scraps to try out this binding. The best thing about coptic binding is it lays flat when you open it- perfect for sketchbook purposes. In fact my favorite sketchbook ever was a handmade, coptic bound book made by Michelle Wilson.
If you're interested in how to do coptic binding I found this website tutorial very helpful! I'm going to have to do another book project for my watercolor class so I hope to do a more normal-size book with a LOT of pages to show off the binding.