i dont think anyone is going to order 19" wheels just to take off and sell them unless you are paying above market and the cost for replacement wheels. It just doesnt make sense.
like if you want to pay me $1500 to order my config with 19" then pay $2,000.00 for the winter aero's and another 1000 for replacement rubbers, im game.
over time there will be 19's available as there are more cars made, but its too soon.