Since I really wanted to do this activity with my girls, and it looked like a bit too much measuring and designing for a 7 & 8 year old to accomplish, I created a notebook page with a pattern. There are lines to help with the number placement, but they are light enough that they are barely visible after the wheel is colored. (The wheel pictured above is the sample I did to show them.)
I tried once more to trace down the source before writing this blog post and came up with Robinsunne's Flickr page showing a picture of the multiplication clock that started it all. You can download my Multiplication Wheel Printable if you'd like to try it with your own children, or do it freestyle (as the original was done) by following the instructions linked below.
* (You can read Robinsunne's original instructions by typing the URL into The Wayback Machine.)