I love this!
Some thoughts on embellishing:
1. If you have a computerized embroidery machine, you can embroider/monogram to your liking a center block to strip piece a fabric that fits Bible. I would also play with formatting to stitch out a favorite verse on cover fabric. Showcase decorative stitches in contrast colors or specialty threads if you desire.
2. Why not use lowloft batting scraps to quilt in the ditch, or make a favorite design in quilting if you do not have the Pellon?
3. Could even stitch colored ribbon markers abt 1/4th inch wide and 15 to 18 inches long at center fold where the spine of bible creases.
Nice tutorial! Great gift idea.