Update to my backorder hell:
Ordered white 64Gb a little before 6AM Friday, 9/14. All communication with AT&T CSRs and emails continually stated I'd receive on 9/21. Even though online order status always said "backorder".
Finally called in again today and asked if I could cancel my order. At first I was told that it couldn't be done, as it had already been "sent to the warehouse for shipping". Kept my calm, asked if there was any way to cancel it, as my local AT&T stores had plenty of 64Gb stock. She put me on hold, then did a conference call with Customer Care. Order was cancelled within minutes, and my upgrade eligibility date was reset immediately. I made sure to get this verified before ending the call by dialing *NEW. Drove 5 minutes to my local store, picked up a 64Gb black (they were out of the white I wanted by that time), and I'm all good to go now.
Moral of this story is...I'll never freaking pre-order (especially through AT&T) again.