If you ask at a shelter, they will usually have already checked which dogs they have are good with cats! It is more of an individual thing than a breed thing, I have found. And it doesn't need to be a puppy, in fact a slightly older dog may be less likely to harass the cat. As you said your cat is fairly placid, you needn't worry about whether a sight hound would be a problem necessarily, they do like to chase things that run, but ...

If you search for a dog on Petfinder.com, they have a little symbol for whether a dog is good with cats or not for each dog.