I've been on the hunt for a good guardy breed for a long time, with DA and SSA being the biggest disqualifications on the list.
Sadly, that does knock out a lot of good guardian breeds. Especially SSA. Dobermans, all of the shepherds, and most molosser breeds have a pretty strong chance of being SSA. Enough that I personally don't feel comfortable bringing one into the house with the male and female borzois.
This is what I narrowed it down to:
Tibetan Mastiff - Pros: tends to be good with dogs in the same household. Cons: read this post,
http://www.chazhound.com/forums/showpost.php?p=2097960&postcount=6the individuals in that post sound 100x more intense than any fila I have ever met, and I've got a fair few under my belt now.
Kuvasz: For a guardian breed, I love love love love love kuvasz. The dealbreaker for me is the giant poofy WHITE coat. My climate is horrible for poofy white dogs. Hands down. Other than that I would own one in a heartbeat, and for people
experienced with guardian breeds/independent dogs that are looking for a social, gentle family dog that will die to protect you, they would be at the top of the list.
Katalin was extremely well socialized and well trained when she came to stay with me. She also has a really good, stable temperament. She had ZERO reaction to rude dogs running up to her off leash or lunging/barking at her. After an initial assessment to determine whether a-hole dog was a threat to the human holding her leash, she'd just kind of shrug and put them on ignore no matter how rude or loud or aggressive or obnoxious they were. It was one of my favorite things about her. She also welcomed people we invited in, and wanted to eat people we didn't. She was very social and gracious in public, and enjoyed people petting her and telling her she was so pretty.
She also was great with my dogs and non confrontational with Strider when he decided he wanted to eat her at first. She did every kind of appeasing behavior to try and diffuse the tension. He did warm up to her and become good buddies after a couple of weeks.
The big thing to remember is that came from the ideal combination of a fantastic temperament and being raised by someone who was totally dedicated to her socialization and training. I've never met a badly raised/bred one so don't know how bad they get when they do go wrong.
Azawakh: Okay. So they don't look imposing. Especially if it's cold and you have sweaters on them. lol. Regardless of their size/looks, they have been used extensively as livestock guardians in the Sahel for generations. They get along great with other dogs in their own households and often outside their family. They LOATHE strangers. They are very vocal about it. Many azawakh breeders have emphasized to me that it may take months for an azawakh to warm up to a new person, and that's totally normal. They also have all said that a stranger will not be able to enter your home with an azawakh loose. They won't allow it.
Filas: They are intense as guard dogs. They can be safely taken in public, provided you socialize them and start out with a dog that has a good stable temperament. One of my friends that breeds them has a wonderful male that won high in trial at a regional protection trial. He goes out with her all. the. time. Busy places too, like bus and train stations. They have a super close and trusting relationship though. Filas tend to be better with other dogs and less prone to DA than some of the other molosser breeds.
I would hesitate to recommend a CAO or CAS. True, there are lines that do well with other dogs. But then there are lines that were bred for dog fighting. I can only think of one line I would personally consider a dog from, and don't know if she is even breeding any more. Many of them are also VERY intense guard dogs, on par with the Tibetan mastiffs in the post linked above.