No one mentioned has anything about a design I saw in the University of Idaho's Cow/Calf Encyclopedia.

They show a cornerpost (which surely must be set in concrete) and a brace like an "N" post.  Then they have another brace laying next to the ground.  It is fastened securely to both the cornere post and the "N" brace.

A flat rock or a bit of concrete is put on the ground where the braces come together.

When tension is applied to the post, the braces redirect the force down on the junction of the two braces. 

I never figured out why someone discovered this until I nolticed some places where the fence is on almost solid rock.  Only one hole to dig.  I have never seen one of these in use.