I don't know of a Deva salon in DFW, but the Styling Hutch in Plano does the Ouidad method and it has literally changed my life. The stylists are amazing and the atmosphere is so relaxed. My hair has never looked better! Check out their page here on NC.
Located in Plano at the intersection of Coit & Legacy- so near to 75, 121 and the Dallas North Toll depending on where you live.