Here's where they all are - Long Beach California! usitalongbeach.org/ There's a fresh item on the front page of Sailing Anarchy extolling the virtues of the Tempest used as a sail training class. There is one that races on Middle Harbour in Sydney in the Summer Monday night races but it looks pretty shabby compared to the pampered US fleet. If you can't find a Tempest you might look at a Jubilee for something not quite so slippery but great value and with good competitive racing.
I'm guessing no luck finding Tempests? I used to have KA-7 but it had KA-15 on the sails. Dad bought the boat as a mooring minder and we put in a little time to bring it back to life. Ended up with a great boat and sailed it heaps on Pittwater. Not really sure what happened to it. That was about 30 years ago though, mid 80's if I remember correctly. We bought sails second hand from a funeral director up in St Ives, he had all his old sails stored in caskets in the basement, quite funny really...