While the AT&T Nokia Lumia 1520 is pretty cheap at only $100 on contract at the minute, it is also relatively handicapped compared to the international version, which has double the storage and comes with built-in Qi storage, meaning no need for a case which would make the large device much thicker.
Expansys USA is now selling an unlocked version of the handset for the US market with the full 32 GB of storage and Qi included.
Unfortunately the trade off appears to be that the handset does not support the full range of AT&T LTE frequencies, lacking the 850 and 1700 Mhz bands, and only supporting 800/900/1800/2100/2600 Mhz.
If you are willing to make the trade off however you can find the handset at Expansys here.
Thanks Mark for the tip.