Took my 2 year old to Germa's. 2 sisters run the salon, both from Africa and they are very nice although a little paranoid about keeping the 4 deadbolts on the door locked.
The lady said my daughter's hair was too short for cornrows (it wasn't actually) and did box braids with extensions. They came out really cute but it took a long time. She charged $60.
The most recent place I took her was JC penney in the walden galleria... I think they have more than one person who can do braiding. We had Whitney and she did it fast and it came out great.
Good luck and let me know how it turns out!