A leather worker (saddle shop not shoe shop) can thin the leather to almost any gauge using a crescent-shaped bladed tool. In strapwork, a skiver is used to thin the endpart of the strap that will be turned over and stitched down over a buckle-- the strong thick part will go over the buckle hardware and get progressively thinner as the end goes on to where it was cut for a nice, neat disapearing edge. You can ask one to "skive" the area around the button hole and then sew a thin reinforcing material like ripstop nylon or fiberglass tape on the underside to restore the strength lost by the skiving with a nice finished look.

~Susan