I GOT IT UNLOCKED:
No I'm not going to link you to some sketchy site that I secretly work for only to have them tell you their "servers are down" or whatever, I got my ATT Lumia 920 unlocked through ATT itself. Here's how I did it:
THIS WILL ONLY WORK IF YOU HAVE AN ACTIVE ACCOUNT WITH AT&T (NOT PREPAID):
Called their international number from outside of the US
Gave them my account information and IMEI and asked them to look into an unlock
Got the predictable response that the phones weren't unlockable until June or something
Asked the CSR to make me a support ticket anyways and forward it to tech support
4 days later I got an email with a working unlock code (although the instructions for plugging it in seemed to be for old nokia featurephones, not Lumias, so you have to google how to do it)
Hope this helps you guys! I made an account just to help out, coz I think it's absolutely ridiculous that they won't unlock their phones.
Cheers,
Josh