I think sometimes we forget that most people aren't looking for a dog that is the perfect definition of the breed standard, and while most of us on this forum understand what a true GSD should be, there are many varying opinions on this. I've been a GSD owner for about 5 months now and have developed my own opinion based on what I read here and also from what I hear at my local GSD club. But when I was looking for my first GSD the King, Shiloh, and "big boned" definately sparked my interest. This was of course before I knew what I wanted out of my dog. As much as most of us don't want to see these large GSDs bred, they will be, because there is a market for them (and the breeder's websites make quite an argument on why it is a better dog). There were many times when I thought, "Wouldn't it be cool to walk down the street with a 150 lb german shepherd." But then say you do get a very prey driven one, at 150 lbs thats probably uncontrollable.
We have to remember that as much as we don't want those dogs called GSDs, to the rest of the world they are exactly that. I can almost guarantee that a 150 lb saddleback would be considered more purebred by most people than my sable pup (6 months ago I would've been in that camp). These are probably dogs that should have their own breed, but because of their close ties to the GSD they won't, and all we can do here is warn of any kinds of issues these dogs might have due to their size or questionable temperment.