I would also like to suggest freecycle, craigslist and the classified ads section of petfinder not just those ads from rescues and shelters to look for a dog. So many people are needing to rehome their animals now and she may find just what she needs there. An older dog would be perfect, past the accident and chew phase. She will also be able to talk to the owners to get a really good idea of the dogs temperment, likes, dislikes, be able to see the dogs reaction in their home environment as well as how well the dog interacts with the kids (outside of a stressful kennel situation). A loud barking dog (size of dog does not matter) at the door will make most people back away from the door. True in some states a sign will not legally protect you but sometimes signs can be a deterent (except for those pesky door to door salesman, guess they can't read "no trespassing" among other things).
I second that a trained GSD is not for the weak or faint of heart. My oldest DS is in law enforcement and trains (for enjoyment) and there is nothing more beautiful than watching these dogs work. To those that have not seen it before, it can be scary to view the first time. We have even had the pleasure to meet and watch those dogs that work for law enforcement up close and have seen them in action. These dogs require that you work them on daily basis reinforcing training and exercising, and in itself can be a full time job. A "retired" dog would still have all of these requirements, and I believe that once retired they are not allowed to go to "pet" homes because of the liability issues. Some agencies give the handler the option of the dog continuing to spend the rest of their days living in their home.
My brother and I were terrorized by the neighbor's poorly trained and poorly bred GSD growing up. If you would have told me 5 yrs ago I would own one I would have had you committed. Small and fluffy were more my speed.
When the time came that I needed a service dog, my son went to a reputable breeder after searching the country for just the right dog and found a "washed out" dog(meaning she did not have the bite drive needed for competition, and she was from excellent west german show lines). He and my husband brought her home to train as a service dog for me. This was after she was tested for temperment heavily among tons of other things. She has her CGC certification and my youngest took her for 4-H for his dog project. She has been a huge asset for me. BUT....she has been HEAVILY trained on many, many things. I would not have personally attempted this had my son not already been a trained handler and had extensive experience working with this breed.
The insurance company came to the house yesterday to take pics for a new policy, not sure if this company will insure or not now because of my shepherd. Have your friend check her policy first, some have restriction even on mixed breeds as well.
You are very literal and I was being a smartie 
