On border of Granite Bay and Roseville 95661 there is a brand new home of 3680 Square feet listed at $985,767. Including the 20,000 square foot lot. A bargain at $267 per square foot.
If the value of the half acre lot was $200,000 and the builders gross profit is $100,000, I would estimate it probably cost them about $685K to build.
So if a production builder can build for about $185 per square foot, it stands to reason that your custom builder should be able to build custom home to your specifications for about the same or a little more, and of course add his profit margin to that.
3,000 square feet at $185 per foot. = $550,000
Add to that your builders profit margin. + the cost of the lot. + any extra cost features you may want such as
swimming pool, elevator, five car garage, workshop, barn.
By the time you add in your cost of an average lot your budget is in the neighborhood of $300 to $275 per foot suggested by Ron Thomas, Eddie Martini and Zac Bacon.
I would fall over in my chair if you could have a nice house permitted, built on a 95661 lot, and landscaped, for less than $267 per square foot
That is why people mostly buy used, or buy from a production builder (your agent can help you with that)
Remembering the old saw about taking twice as long and costing three times as much; I suggest you should allow for $300 per square foot.
But, why are you beginning this way; an Architect is your best source for what you need, and I would not look for architects here on Trulia.
As Zac mentioned below there are several variables to factor into a new build. I have projects as low as $125/sqft and others around $275/sqft. I am a REALTOR so these are all price/sqft that you as the BUYER would be looking at with contractor fees ect already factored in and in some cases these prices could be achieved WITH LOT PURCHASE MONEY factored in.
I'd be glad to put you in contact with great local contractors that can accommodate you from start to finish!