There's a place called Petite Pooch. My g/f has taken my dog there before. It's right in the vicinity of Marsh/Beltline. I can't give exact directions, but it's on the Southwest side of the intersection. Here's a link.
Sorry I was in a hurry when I posted originally. Yes they take large dogs. I take my Great Dane and Golden there when I'm on vacation. Tia is the owner and I work with her husband Steve. They are huge animal lovers. Thanks to Chris for posting their website.