I was on U Street last night for the election.. and LTE lit up on my iPhone 5 for the first time last night.. Not sure if it was in testing or if its officially released, but I never dropped connection in that area last night.
Edit: Speed Test from U & 14th NW http://www.pictureshoster.com/viewer.php?file=ifq0dz73i5ucaxgjnrqg.png