Well,
This "was" a listing for it on ebay a while ago. You've got a couple options. One, contact the links that other posters have linked or, simply go buy a piece of masonite and, trace out the pattern and, leave enough for a handle and, you're done. Many folks have made theirs that way. That large fastener is not on there very tight. At least it's not supposed to be. There are some that put gorilla tightness on it but, it's not necessary. It's detented in design so, it's not going to back-off on it's own. So, there's no need to get it ultra tight.
Scott
ULTIMATE HUB NUT TOOL | eBay