The history of the rubberset brushes starts in 1831 in New York and continues until now. There is an excellent website about its history, versions and related forum. I will be not repeating the story. You can see all the pictures of how the shape and material has been evolving along time. Nice source of inspiration.
The shape of this brush is well and widely recognized in the wet-shaving community. They are being produced out of wood or metal. I wondered if this can be followed but made of ceramics.
I tried to do it from stoneware clay. The handle fits for 28 diameter brush. I admit, I’m satisfied with the result.
The other approach, from the same firing, is made from marbled porcelain. Here the attempt was a bit different – to follow the modern design of rubberset. The difference is visible at the top (smaller diameter of the top than the base) and in number of flutings in the handle. It fits to 26mm knot.
At the end I would redirect you to other attempts to follow the rubberset design. Here is nice design of charcoal. There are also other very nice sources of pictures and reviews.