Peter, It is too bad you are not in South Orange County. I have been renting a small fleet of Cannondales to people just like you, and I give discounts to forumites. This afternoon (Saturday) I am also leading a 4 hour hilly tour that you would be welcomed to join. The link is in my signature.
I place of that, though, I think Helens Cycles in Santa Monica rents some pretty nice bikes. Give them a call and they can hook you up.