I went into a large AT&T store yesterday to ask if they had any 6 Plusses. She said no. I asked if they are getting any shipments of 6 Plusses. She said no. Then she said for a 6 Plus, I need to place an order and that it would be shipped to me directly from Apple in December.
I am assuming there was hope that an AT&T rep would find the thread an anonymously give tips here.
Stores seem to be reluctant to tell you anything. I have heard "we get shipped stuff on a specific day" all the way to "we get shipments all the time, including mid-day" from AT&T employees.
Due to a glitch in my market versus area code, I am stuck upgrading through a core ATT (or online) store, or I can wait for the glitch to be ironed out, though I was not given an ETA. I've tried asking multiple stores but I have effectively given up for now. I have already spent more time on this than I believe it is worth.