I know Auzze makes them. We've made a few at the Melbourne hackerspace.
I've got a 3 axis mill so I could probably make one, but I don't have any suitable bolts. I'm also currently in Queensland working, so wouldn't be home till sometime on the weekend.
If you've got some bolts, and are somewhere near Caulfield, PM me and perhaps we can sort something.
Note: I always recommend making a bolt specifically to suit the extruder, rather than using washers to make the bolt match. Much less prone to error.
