I was visiting in Austin TX this past week and I can report 4G LTE coverage in the Tech Ridge/Harris Ridge area of the city (way north, east of I-35)
I ran 3 speed tests at different times while out there:
10/31 @ 9 PM = 2251 Down, 373 Up
11/1 @ 9 AM = 3591 Down, 1928 Up
11/1 @ 6 PM = 4953 Down, 1286 Up
Coverage was in and out, first time lasted just a few minutes after I discovered it. I had wi-fi indoors to internet cable so I ran the speed test and then connected back to wi-fi.
I also got 4g LTE at Bush Continental Airport
11/6 @ 8 AM = 3051/5105/2261 Down, 4172/4846/4174 Up (ran it 3 times within a 15 minute window)