Charles Chocolates makes those caramel apples for Williams Sonoma. Sometimes they carry them in the shop I think. You might give them a call. They are in Emeryville. How far will you travel? I know a source in Napa.
Thanks for reminding me. There is one in Fisherman's Wharf. Nearby on Pier 39 Fudge House has caramel apples also. I have read that while Fudge House has more varieties, the apple itself is tastier at Rocky Mountain.