Matt,
Master of the obvious here...only things I can think of are is to see if your dealer can order you one, poke around on the Yosh website and see if there is anywhere you can drop a line to asking for help, hit the salvage yards, check hardware stores to see if there is something else you can use with a little modification (without being plated it will probably be ugly in short order though), and post this same thing in the "parts wanted" section here. Maybe someone dropped their bike on the exhaust side and has spare hdwr.
How in the world did you come up missing one?
Good luck!
Steve