Several dealers in my area all told me 8 - 12 weeks (or longer) if it comes from the factory. Much sooner if they can find one with your color and options, unsold enroute from port to another dealer and do a swap.
I placed an order for a Flint Mica V6 Sport last week. I'm very picky with the color. The dealer told me 6-8 weeks or sooner. Apparently they are usually aloted several units and if he could time it right (i.e. put in the request before Toyota paints the car) we could get one with my options and color choice sooner. You could try and ask your dealer if he can do something like this for you.