As a former Military Working Dog Handler I'm going with what I'm partial too which is your good old German Shepard.
Until recently, I've had GSD's all my life, and they are the greatest. Loyal, devoted, absolutely fearless, and self-appointed guardians of kids.
That said, I wish you luck in your search, Porkskin, but I'm afraid I have to close this one as off topic for tactics & training. Maybe some of the Members can PM you with suggestions.