It really would be best to have someone who knows about bunnies taking care of them, since the person will know the signs if your bunnies become ill, but also how to care for and play with your bunnies.
there are rescue groups in southern CA and many rescues do boarding as a fundraiser. I tried to look around their websites and didn’t see anything listed about rabbit sitting, but it seems like trying to contact them would be a good idea, since they might have a good reference for you.
you might try this group
long beach bunnies 562-964-3248 http://www.longbeachbunnies.com/ (the site looks kinda out of date though)
bunny bunch: http://www.bunnybunch.org/about2.html
below is the vet recommended by House Rabbit Society in your area, you might call there to see if one of their vet techs might want to bunny sit for you or if they do boarding. I’m not a huge fan of boarding at vets offices, since they often don’t have a way to let bunnies have run / out time.
Dr. William Ridgeway, Dr. Carl Palazzolo (562) 434-9966
Long Beach Animal Hospital
3816 E Anaheim St. Long Beach, CA 90804
San Diego is pretty far – but there’s a bunny B&B there. http://www.bessiebunnys.com/index.htm