Not being a golfer I have no knowledge of what is out there, save that I met one gentlemen that used a hard style [PVC] traveling golf bag. Complete with a lock and checked it in along with his luggage. Of course his blades were disassembled, packed in bubble wrap and hidden within a small group of cheap golf clubs, and declared it to be sporting equipment. It worked for him, but I must note that he was not on an international flight. Just domestic, and it took place before 9/11.
L Fitzgerald