Check out airbnb.com, or homeaway.com. If you find something that resonates with you in areas like Bishop Arts, Uptown, Oak Lawn, or even Lakewood/Swiss, these were always the areas that resonated with me most and perhaps you might enjoy your stay while in Dallas a bit more.
Also, go ahead and call Power Properties, ask for Braden or Craig, and ask what they might have for you short term.
Maybe extended stay hotel if you don't have furniture and don't want to mess with turning on utilities.
Click below for extended stay hotels.
Send me your email and I can hook you up with apartment locator for the apartment search.