It's not a great deal and since you could probably get a new '16 (without ACC) for thousands less, you are paying an awfully big premium for ACC. I would try to work a couple dealers against each other. Give them all a price you want to pay "out the door" on the order and e-mail it around to some internet sales managers and see if any bite. Heck, as a custom order you might be able to go to some other GM dealerships that may not deal exclusively with Chevrolet (like Buick for example).
I would also do a nationwide search (say on Autotrader) for new '17s with ACC and see what the price when already sitting on the lot. You might come out ahead by getting one a few states away shipped to you if it meets your needs. At the very least, you can use the price you find as leverage to get a better deal on the order.
In my opinion, though, it is much harder to get a good deal on a custom order. Dealerships are always more motivated to move steel already on the lot and they receive many more incentives from GM to do so.
***2013 Black Volt, Leather with Ceramic White Accents***
***17" Sport Wheels, Nav, Bose, SP1***