Personally, I like
http://www.elescorialsb.com/outside_home.asp
Keep your eye on it in case something comes up. Residents will occasionally offer up their furnished places for short-term leases.

Not on the beach, but a fantastic place chock-full of history:
http://www.sanysidroranch.com/

And vrbo has some good choices. You can always hire daily maid service.