I've researched this for many years - I've felt for a long time that our lifestyle wouldn't be fair to a dog. Now our lifestyle has changed. There are certain things I want in a dog - intelligence, trainability, size are all important to me. Also a dog that is athletic, but not one that needs to work all day long, like a German Shepard or a Border Collie. I also like a dog with an imposing appearance. I've always loved the way the Pit Bull type dogs look, but they're not known for their easy trainability. I don't prefer dogs who are "everyone's" dog, like a lab.
My second choice is a shepadoodle - a Shepard/Standard Poodle mix, which surprisingly shares many of the temperament traits with the Dogo. I prefer the Dogo's appearance, however.
That's cool. I hope you find what you want.
Given your criteria, I would also take a look at Rottweilers. Good ones are not too hard to find anymore.
Good luck.