California Association of Realtors' produce reports about California real estate - forecasts, county summaries, California affordability index and much more. Much of their content is freely available, while some is for members only.
Local realtors associations publish details about their territories. Search the internet for realtors associations for desired area.
Association of Bay Area Governments and Metropolitan Transportation Commission for the Bay area - see their easy to use Vital Signs for the Bay area by county. Contact the MTC-ABAG library for any regional transportation and regional growth planning resources.
Southern California Association of Governments Forecasts and Local Area reports for the more urban Southern California counties. The association is responsible for formulating priorities for housing and economic development in their area.
Business Times and regional Book of Lists are available online for major US economic areas. For the Bay area there are East Bay, San Francisco and Silicon Valley editions of the Book of Lists which list the top companies in various fields and includes data on the largest properties and other relevant data for real estate developers or investors. Book of Lists is available in the online Business Times package.