my friend that had thai ridgebacks said they used training methods more like how you would train a cat with that breed. Not sure what it's worth, just tossing it on the pile.
As for a breed suggestion, have you considered a standard poodle? Most landlords do not have any objection to that kind of dog because they don't have a rep, but let me tell you, the VERY MOST PROTECTIVE dog I ever owned was one. Had a friend that was world champion Schutzhund "guy in the suit" I forget what they call it, but he was the bait guy for schutzhund dogs and WC at it, he saw my big poodle Bailey and busted out laughing, and said Why???? Then he started to do some informal temperament testing and then did more and more and said some words I can't type in BYC, and said that dog tested higher for protection, bravery, intelligence, tractability, holding his ground against a threat, than MOST of the dogs he had seen come over from germany already trained. This was a fifteen month old puppy. Anyhow, lots of people I know that have them feel VERY SAFE with that kind of dog looking after them and their stuff. He was pure white and I used to keep him in a show cut and take him everywhere with me and leave him in the car with the windows down and people would say "Aren't you afraid someone will steal that dog?" I would say, if they can steal him, they can have him! He would protect that car from anyone within five feet, never hurt a flea, got along with teacup sized dogs, didn't chase cats, didn't destroy furniture, didn't shed, didn't bark without cause, would stay in a three foot ex pen with no clips. I could tie him up with dental floss and he would never break the "leash" as it were. They might look like big old high falutin' sissy dogs, but there is a LOT of GOOD DOG hiding under that prissy hairdo, lemme tell you!