Great link....lists several great places to eat downtown.
http://www.yelp.com/search?find_desc=gluten+free&find_loc=Dallas%2C+TX
Would love to go here for date night...
http://www.konagrill.com/Index.aspx
Bavarian Grill
Chipotle
Macaroni Grill
Olive Garden
Outback Steakhouse
P.F. Changs (yum)
Rudy's
Saltgrass (Eldorado and 75)