Irish Wolfhounds are in the "slobbery-wanna-be-lapdogs" range as well. They don't fit your 50-60lb range though.
As someone who has spent a fair amount of time training dogs and knowing how they tick, your needs are a bit contradictory. My Pit is an amazing pet because she's not an Alpha. She lives to please because she knows I'm the alpha. It makes her a great pet, but she just got bested by a squirrel the other day. Last month she couldn't get the upper hand on a cricket. (tried to video it, but she gave into the insect's iron will before I could get my phone out).
Having a dog that is big enough and protective enough to ward off a pack of coyotes needs REALLY special training and discipline to prevent it from becoming an intolerable pet. It's a bit like gun ownership. Anyone can buy a 30-06 to protect their property, but in the hands of an untrained person it is a lot more likely to end up being a liability.
Here is one thing you need to know about dogs; They don't know size. They know alpha and not-alpha. The only way they determine who is alpha is to scuffle about it. What this means is you could have a 5-lb Chihuahua that will run right up to a coyote without seeing size and end up being a snack. You could also have a 100-lb St Bernard who will do the same thing and end up being a three course meal. You need the combination of a strong desire to protect in a non-alpha dog with enough size to get the job done AND comprehensive training so the dog isn't an shiny happy person. But rest assured, a protective dog (even many unprotective dogs) will follow their instinct and chase a coyote. Whichever one wins is a toss up depending on which coyote they encounter. The winner will be the dog with enough size AND the right protection drive.
Owning a dog with strong alpha tendencies is incredibly challenging, regardless of breed. My ex has a Pit right now that she is rehabbing from being a fight dog. That dog is a lethal combination of alpha tendencies, zero trust of humans, and a history of winning. Add in that he was not neutered AND he is blind in one eye and feels over-vulnerable means that he would likely kill a bear to protect her, but he is a hideous pet. She's working with him and making great strides.
Long story short, it takes a very special dog to be a good pet and a good guard dog that doesn't die on its second encounter with a coyote. It can be found, but don't just buy a breed. Just like people, you have no idea how the relationship will become until you've owned it for a while. Get a dog because you want a dog, but expecting the dog to behave a certain way is no more realistic than expecting another human to do the things you expect or want them to do.
I'm reminded of a repair shop that used to be owned by a guy who trained police dogs. He had two Rottweilers that lived in the shop. When he locked up, they were vicious killers. Seriously. Once he opened the shop the next morning, they were lap dogs who loved their bellies rubbed.
When looking for a dog, it is easier to build up a dog than knock it down a peg. Look for a dog that approaches you meekly. Be the alpha to a dog that doesn't need to be reminded that it isn't an alpha, and chances are it would die for you and defend your property from a frog. Don't go for the damaged ones... if they evacuate their bladder and roll over in fear, move along. Look for the ones that crave your interaction from a posture of humility. If they jump all over you and lick you to death, they may not have much protection instinct. But, again, it is so hard to tell. You can't buy a guard dog that is a good pet. You buy a dog and it might be a complete failure at everything you want it to do. Getting a dog is a first date. She might end up being the love of your life and be a perfect match, or you might date for a year and realize that she's just not right. It's not her fault, its just how your personalities mix.
The funny thing is, I'm not a pet person at all. I prefer house plants. But you couldn't pry my Pit from my hands with a shotgun and a baseball bat. We found each other. I didn't want a dog, but after meeting her, I wanted HER.