Looks like this should work on US models (except AT&T variant because they screwed everyone over and swapped to PMA instead of Qi charging).
http://www.aliexpress.com/item/Back...Replacement-with-NFC-Function/1997230941.html
Yeah, I researched this earlier to make sure this was possible (getting another battery cover). Having the 4 pins is key. Just the 2 is NFC only. The greed of the U.S. carriers are limitless to take away a standard feature and make you purchase an accessory for something that already comes with the phone.
I made sure I could get wireless charging and that the bootloader was unlocked before I pulled the trigger on the G3. Otherwise I probably would've waited around for the Nexus 6 (?). Thank goodness for T-Mo. Super-fast speeds, unlimited data and they don't mess with your phone (other than this no wireless charging nonsense).