I had never seen it before - but I made a tape measure into a geocache. I covered the tape measure part in white labels, turning it into the logsheet. I then put camo tape around the measuring tape and tied it high to a tree. I attached fishing wire to the end of the tape measure, so to get it down you just simply pull the fishing wire, then sign the measuring tape :)
this is the case I bought.
I found this site to customize my log. The site is in a different language, there may be a way to change it to English but I didn't need to go through the trouble as it is easy to navigate through, (it provides the option to change the words on the log to english). I liked that I could create an easy custom template.
edit: actually, I think I've changed my mind and want to customize my log using different themed paper.