I got LTE at State Farm Arena in Hidalgo. Ran a couple speed tests: first averaged 4.66 Mbps down and .25 Mbps up and the second was 3.98 Mbps down and .40 Mbps up.
It's a better than the usual <1.00 Mbps down that the rest of McAllen/Edinburg get.
Also, this was only outside the arena. Inside, I couldn't even keep a steady 3G signal.
I've also gotten LTE at Nolana and Exp. 281, 281/83 interchange, and in Alamo. LTE didn't stay on long enough for me to run a speed test in any of those spots though.