Actually there are scarce few "knife stores" around the Dallas area. Probably the most complete is House of Blades over in Fort Worth. There are smaller knife shops in Willowbrook Mall (Plano), Arlington Mall, and Grapevine Mills Mall, but they are really limited. There are a couple of Cabelas in the area, and they've recently upgraded their cutlery stock on decent, mid-range production knives.
Your best bet may be to visit one of the traveling Gun and Knife shows that frequent the area. There's one this weekend at the Dallas Market Hall, and another in two weeks in Fort Worth. Knife dealers from all around the area come to those.
Good luck and enjoy your stay in Big D.