I have seen several pictures over the last year that have been taken from above. They were mounted overlooking a trail, maybe 8ft. high. You just have to make sure your PIR is pointing in the right direction. It really gives the pictures a unique look. My cousins photoscout got attacked by a bear, so he mounted it up in a tree overlooking the trail, and got some cool photo's of a mom and three cubs, and a huge bobcat. I will definately give it a try when I find the right tree hanging over the right trail.
I have one mounted about 10 feet off the ground strapped to a branch of an apple tree, the only bad thing is I have to climb the tree to get the film! It does give you a unique perspective, and seems to greatly reduce false pics.