Probably pretty big, but it depends. Also Lorraine, why is it a bad mix? All of those dogs listed are great dogs, including the pit bull, if that's what you did't like about the mix. Tinkles, i think it will be a beautiful dog :)
No telling since it's a mutt. Best estimate would be average the weights of the parents. Or if you don't know their weights look up the breeds. Add their average weights together and divide by 3. Dog should be around that weight BUT could be as light as the smaller breed or as heavy as the larger breed.
Just so everyone knows she turned out GORGEOUS and she's EXTREMELY smart. She learns to do tricks within 10 minutes at a time. Her dad is full white german sheperd and her mom is German sheperd, great dane, pitbull mix. She's beautiful. Good proportions looks mostly like a German sheperd. Here is a picture.
Pretty damn big, but it sounds cool ^^ Keep in mind that most of the time, the bigger a dog is, the shorter its lifespan will be. Pushing that aside, big dogs are amazing <3