T-Mobile band 12 LTE sighted in California, Colorado, and other states
T-Mobile has announced a few official Extended Range LTE expansions in recent weeks, like in El Paso and the Jersey Shore. And there have been a few unofficial band 12 LTE sightings, too:
Buena Vista, Colo.
Bergen County, N.J.
Sources: Reddit (1), (2)
Thanks, tazzman101, Joseph, and Adam!