Hi Judy,
As a thought, have you seen the nebari of the western USA native Vine Maple, Acer circinatum? and the Moosewood maple? Acer pennsylvanicum? Both are in the same section and series as Acer palmatum, and Acer circinatum has been used commercially (because it was cheap to get) by a couple Pacific Northwest wholesale JM propagators. Unfortunately from my memory, I don't recall either having ''better'' nebari, but my experience is limited. If you can get a copy of Vertree's Maple book (my local public library had it), there is a page listing which maple species are good understock for other maple species. Acer is one of the more particular genera who are very restricted in their compatibility.
As others mentioned, almost any species in prunus can be grafted onto another prunus. Similar with Malus. Each group has its own unique compatibility quirks.
And as
@markyscott mentioned, the why? is the key issue. Majority of commercial grafting is for disease resistance, climate adaptations, or to beef up or dwarf growth habits. And where cuttings, and or tissue culture won't work, grafting for reliable quick propagation in wholesale quantities is another reason.
A few maples are in tissue culture, result is trees that are very much like trees from cuttings. But the protocols for tissue culture require a lab and serious set up money, not usually done by small scale producers. I know of one such lab in Netherlands where the minimum order is 10,000 plants if you want them to put something into tissue culture. Your cost per plant will vary with the size and age your require them to be brought up to, but it adds up quick. Emperor I, Bloodgood and a few others are the maple cultivars I heard are in tissue culture.