A fellow-barefoot runner has run with the Tuharamara (sp?) Indians down in Mexico and discovered their ultra-simple sandals they make. He copied their style and explains how to make your own sandals on his website, http://www.barefootted.com/.
I think he posted somewhere about the straps wearing out on the sides where they go through the soles, so I came up with some little tabs on my design for the straps to go through in such a way they never come in contact with the ground.
The side tabs are positioned just in front of the ankle bones. I made my tabs a little wider than necessary. I may move the hole closer to the bottom of the sandal and keep the tabs smalled - but then, I might not. I figure if they are a little longer, they will bend easier. So maybe I'll just leave them the way they are.