They have condos at Newport Beach - you can do a search. There are also beach cottages at Crystal Cove (between Newport Beach & Laguna Beach), but they are extremely hard to get in to.
I don't know if the other poster meant VRBO.com, but it's vacation rentals by owner and it might be a good site to check, but I would suggest on your park days staying closer to the park to save yourself the drive.
We're doing this, too, and did it last year. We like to stay in Hermosa Beach near the strand. You have miles of a walking/biking trail along the beach and the beach itself is fabulous. We used VRBO.com last year and are renting the same place this year. It's about 45 min. from DL. We're going to spend 2 nights at Hojo at the ent. rate to make it easier to go more than 1 day to DL.
I think I would like to try San Clemente next year but we need to check it out when we're down this summer and see how it looks. It's so hard to get a feel for a place just from seeing it online!
DEFINITELY Crystal Cove Cottages if you can swing it. They are awesome for the price! A little far from DL, but worth it. Second to that, I'd say look into the VBRO for rentals in Huntington Beach, you'll get the most for your money there and it is only 15 minutes from the parks.