Thanks for the compliments MCK. I certainly don't know everything, but this is what I've learned so far...
As far as Shepherds go, "built right" means watch the rear end on the american bred dogs. The ones with the severe "low rider" back end are not gonna be a suited for high speed pursuit. The Belgian, or european bred dogs seem to have better structure as far as working dogs go.
I currently have 3 bird x cur females I'm using, but I don't care how a dog is bred as long as it's built right and is game. Here's a picture for reference of what I look for structure wise. Deep in the chest(lung), adequate muscle(but not excessive), 50-70#'s(big enough to make a big hog pay attention). The hind end is more important to me than about anything... it's the first thing I watch when I'm looking at a prospect. If you've ever seen a puppy, or a bulldog, run and you noticed that the back end just looks like it's kicking out of gear... tracking sideways funny... that's all I need to see to know the dog won't be fast enough for me. I want the dog to move like a leopard, so he must have the build to do it. I look for dogs that move like a rabbit in a briar patch.
"Gameness" is a must for me, this does not necessarily mean catchy however. In fact, I'm more interested in "non catchy" dogs now than ever. Ellie was a prime example of a true bay dog, she was not catchy AT ALL, but she bayed many, many hogs by herself. She was hell on a hog's rear end though... I saw her drag a big hog down many times, holding on to a ham hock until the hog would stop to fight... then she'd just step back and bay from 10 feet. Perfect. That's why she lasted so long and rarely got cut. Two out of 3 of the dogs I have left are too catchy. Sure they catch hogs, but it's just a matter of time before they get killed.
The dog pictured above, Shiner, is just like Ellie bay wise... hopefully she'll make her mentor proud.