Here we have an awesome project. Made around a Mloeskinne brand book, you can use any book or notebook with the same approximate dimensions (8.25" x 5").
This notebook has plenty of room for customization to add any specific pen or any other holders you might want.
This project calls for 6-7oz leather for the outside and 2-3oz for the inside. You'll also need 1 yard of #5 zipper and 2 slides. Don't forget the wide tyvek (3.75") and double sided tape for your card pockets!