Hi,

i would certainly go for an LGD breedif i were you.

newfy, st bernard are out of the question. Not healthy enough, will cost you alot in the long run.

pyr is an option, but too soft and to much of a house pet now of days.

if your dog needs to deter a bear, please don't kid yourself that 1 dog is good for the job. You will put him/her up for failure.

consider atleast 2 dogs if the treath is real. 

Both sarpla or CO's are a good choice concidering a good breeder.

99% of the people think they know what the real deal co and sarpla is, but they don't. 

I don't know if there are any aborigional breeders in the US. I do know quite alot of them in europe.

do consider other LGD breeds. Look for similarities in terrain/ envirioment / weather conditions to pick the correct breed

( look for the less known breeds to have more of a chance for a healthy and good/ correct temperament dog) 

kind regards.

frederik