I think you'll need to bump your post count before you're able to access the buy/sell forum, but that would be your best bet. or possibly keep watching ebay, but the ones i've seen on ebay are a pretty penny.
Only other option I could think of is call
http://www.plowmanscarts.com/
They may have some in the junk parts bin they can sell you, or he may be able to talk you through proper jetting to run a different airbox or filter even. I don't believe there is anybody in the country that knows more about yamaha golf carts than don plowman.