IrvineRealtor might be able to help you out with that. You can check The Inside Tract for a list of the tract names but they charge you for the floor plans.
Check out this agent's website...some informative information about Ladera Ranch. He states that if you send him an e-mail he can send you PDF floor plans. http://www.ronforhomes.com/laderaranch.htm
You probably have to look for a realtor that is a Ladera Ranch "specialist". Most times, when a realtor is the go-to guy... he'll have a resource like floor plans for that particular area.