A new kiosk that I recently discovered in some malls here, Asprey (which has nothing to do with the British luxury goods store) has nothing except watch straps. They have straps in leatherette, rubber, plastic and real leather, all the colors of the rainbow, and a wide range of widths. Even if the way the strap is attached is unusual, they will accommodate the replacement request, spending time carefully slicing tiny portions out of the tough leather.