Moto X GSM Unlocked Developer Edition Comes To AT&T and T-Mobile
The device sports 32GB of memory and features a two-tone design with a white woven back and a black front; the back bears a “Developer Edition” stamp so others can know what’s up. Unlike the Verizon edition of the Moto X Developer Edition, the GSM version doesn’t come with a SIM card, so you’ll have to provide that on your own.

Speaking of the unlocked Verizon version, it’s already out of stock; certainly, that’s due to surprising demand and Motorola will just need to ramp up production to catch up, but if it’s any indication, you should jump on the GSM version post haste if you’re hoping to get one anytime soon.
The site also notes that the Developer Edition could take as long as 7 days to ship.