From what I have been told, the special orders are placed twice a year in February and July and that would be a limited number for each boutique. (Only 10 SOs from my local boutique each time, only for their loyal customers) If you are offered for a special order, you can choose different colors, leather, hardware, lining, piping color, tricolor, bicolor, stitching of your own choice. Then the boutique will check if the colors and leather you choose are available, if they are available, after they place an order for you in Feb or Jul, the bag will arrive within 5-7 months. But if the colors and leather you choose are not avaible for offer, then it can take up to years.
I heard that you can order the bag in tricolor on the choices they already have, but that wouldn't call as a special order.