Did you try Nordstrom Direct? Sometimes if you call the designer specialist number on the website they can tell you if it will be avaible online in other colors soon.
Nordstrom.com already sold out of the regular black during pre-order. Regular black seems to be impossible to find for the sasha mini. Good luck though!
What about saks or bloomingdales? Sometimes in a jam I try Von Maur, they are my litte secret...it's worth a shot!! That bag is great you gotta find it!