Here's what we came up with:
That's mine on the top, and Heather's below. I need to experiment with various materials to use to stiffen the covers. I used 2 layers of a heavy interfacing fused to the fabric with Misty Fuse, a type of fusible web that doesn't gum up your sewing machine needle when you sew through it. It worked well, but the pieces of interfacing were just scraps I had on hand, so I'll need to do some shopping for future journals. Mine has an elastic keeping it closed while Heather has used several strands of bright embroidery floss knotted together to wind around the button. I can see all kinds of possibilities for closures and vintage buttons!
We brought these along to the quilting retreat, and they got a lot of positive attention. Who knows, I may just have converted a few quilters to try bookbinding! I'll definitely be making more of these myself.