These have been cast by several bell founders since the original bells in the 1800s. Most recently, they have been cast by Bevin Brothers Bell Co. of East Hampton, CT. There were several sizes available from about 3 inches in diameter up to about 10 inches in diameter. I do not think that they are currently being produced. You may find the various sizes by searching out a Bevin Brothers catalogue from the 1960s when I know that they were being produced and sold. My mother sold them in the 1960s.
Harry Long, MD