The Moto X Moto Maker program for AT&T just kicked into gear. You can now order a customized version of the Moto X for AT&T, and get the phone on a new two-year contract for just $199.99 subsidized. If you want one of the customized Moto X devices, you can't actually walk into an AT&T physical retail location and get it. If you try to get a custom Moto X from a brick-and-mortar store you will simply get a coupon voucher that you take home and use online at the Motorola Moto Maker website.
If you only want either the white or black version of the device, AT&T retail stores do have that in stock. Sound off in the thread which option you are mulling over for your Moto X purchase. If you go to AT&T's website to grab the device and want to customize yours, it will ultimately redirect you to Motorola's Moto Maker site. Here are link to both below.
Design Your Own Moto X™ - Available Only at AT&T
Moto X by Motorola - A Google Company