There are a couple Red Elms(Ulmus rubra) over 3 feet in diameter that I have wanted to graft and create new ones. The reason being that they may have some DED resistance since elms have been dying around them for decades.
Currently I am trying to graft them on Siberian Elm(Ulmus pumila) rootstock. Siberian Elm is a common elm species in this area, frequently planted because of their disease resistance and tolerance of our Western Iowa conditions.