Postal Service Update (potentially):
I just checked my USPS Informed Delivery Dashboard (linked from a daily digest of snail mail I'm receiving) and there's a shipping label that was created yesterday, the day I preordered, and about the same time (3:53pm) that my iPhone order status changed to "preparing for shipment".
Can others with the 9/23 postal service and 'preparing to ship' status check their USPS Informed Delivery dashboards to confirm if they see the same? This would disappointingly potentially confirm that a random segment of us early-minute preorderers were dumped onto USPS.