Looks like those pockets are riveted at the bottom corners, and I'm guessing either sewn onto the backing board or glued on (or both). Shouldn't be too hard to find some flexible leather, fit and cut out the shapes/sizes you need for certain pipe accessories, and then do the same - Tandy Leather Factory has a handy-dandy lockstitch awl that I used to hand-stitch a sporran, and it works like a charm. Tandy also has a series of books by Al Stohlman on making leather cases, which I picked up on sale a few months ago. They cover construction details, and how to plan out a custom project. Highly recommended.