Update: I was able to get my tracking number by using the AT&T mobile site.
Unlike many of you who used the Play Store to reserve your Nexus 6 handset, I opted for AT&T this time around. I wanted to use this upgrade I had laying around for a while and keep my unlimited data going.
I was able to place an order on November 11 at 11:50 PM CST and I paid $249 by signing a 2-year.contract (lame I know). The estimated shipping date was around 11/18 and 11/19.
Being the Android fan that I am, I checked my email and AT&T order status page multiple times every day. This evening, while doing exactly that, I found that my AT&T Nexus 6 Midnight Blue has shipped via Fedex. Keep in mind that I received no email notifying me that it actually shipped.
TL;DR.. Go and see if your order status has changed and let us know!