I'm an architect in San Jose and I specialize in single family residential homes.
Your first answer from Dave is spot on for Saratoga construction costs per square foot. You can expect a higher cost per square footage because it is a location where homeowners expect high end finishes. But, the overall cost will depend on the design of the home and as Terri mentioned things like how many stories, the foundation type, etc. Is the property a flat site or a sloped site? Is there a home there now that will need to be scraped? Have there been any soils testing?
Time is another factor that is tied to the overall cost of the project. To build a completely new home in Saratoga of that size could take anywhere from 2 to 4 years (from the day to hire the architect to move in) depending on the complexity. You will be required to get a design approval which I would recommend is acquired before you spend money on completing construction documents (drawings).
A town like Saratoga will expect you to hire a licensed architect. They frown upon not having qualified individuals design and create construction documents for the home. I had a client in Saratoga come to me after they had spent nearly $20,000 on worthless drawings because the city would not approve the "ugly" house that they had planned to build that an unlicensed individual had created for them. Not only was the house unattractive, but the design was supposed to save them money by keeping some original portions of the house. However, the "designer" didn't know enough about structural engineering and building codes and if that home had been built, so much of the original home would have to be demolished that it would have been a very expensive ugly house.
So the cost of an architect with structural engineering, city permits and fees will likely run anywhere from 10%-20% of the construction cost.
If you have any other questions that you would like to discuss in private, you may call me at my office (see my website listed below). You can find other local architects by contacting the local chapter of the American Institute of Architects @ http://www.aiascv.org.
Good Luck, Jennifer Kretschmer, AIA