Replacement Leather Bag, Miniature (Item Code: BAGR-M) Replacement Cow Hide Leather Bag for Miniature pipes. The bag is 24" Long x 9" wide; Neck opening diameter is 1 3/8 inch. (609.5mm Long x 228.6 mm W with a 34.9mm opening)
This is the link to Andrew Lenz's web site he covers most questions about bagpipes. This link is for tying in stocks to the bag, where to cut the holes etc.