The first Zoo that I went to (which was the last official ZuZoo) had four of the trail logo's with ZuZoo below it (similar to Jon's idea). It was fairly simple and if you had never been to Moab and run the trails you wouldn't have known what the logo's were, but if you HAD been then you were in the know. It was cool that the sticker tied in the ZuZoo and Moab without overtly stating it. I can't find an image of the sticker online, but I have one at home that I can take a picture of for ideas.