I spent this evening in close observation of the new pup, and have concluded that while there is a lot of Dane in her, she is definitely not purebred.
If I were to pin down any other specific breeds, I would wager a guess at Boxer, and possibly some type of terrier. Her coat, color and overall features give strong support to at least half Dane. Her size, some conformation features and personality suggest several other breeds. Her ears, in particular, look like a cross between a Boxer's uncropped ears and the ears of a Fox Terrier. She is a merle, with coloring similar to this, but with no white.
I'll get pictures up of her as soon as I take some. That task isn't on my to-do list yet. It will go on there once I free up some room on it!