I have many stone fruit scionwood leftover and tried grafting these unto Nanking Cherry.

Nanking cherry is Prunus tomentosa.
Here are the takers, the ones that sprouted, have leaves and still alive as of today:
Nectarines, Peaches, Cherry Plum, Japanese Plum, Russian Plum, European Plum, Native American Plum, Pluot, Plumcots.

Here are the ones that initially took and slowly died: Almond, Apricots, Apriums.

Plans for next year: will graft the apricots over some of the nectarines. Will graft the apriums over the plumcots. Will graft the almonds over the peaches. Will obtain some peach plums, peach cots, and peach x plum x apricot hybrids, as well as peach-apricot hybrids.

Will try to graft Krymsk 5 later this year as a head start for grafting sweet and sour cherries as well. And will have another world record cross-species fruiting tree sometime in the future.

My father tells a family story about my greatgrandfather grafting peaches onto sassafrass saplings. I have searched high and low and have found no evidence (even anecdotal) that his is remotely possible. It occurred to me today that my great grandfather may have been using wild cherry rootstock instead of sassafrass. I will continue to look into this issue as time allows. If you hear of anything remotely similar please let me know. Yadda out.

I have successfully Joe's Bark graft method the following to my flavored king plout:
Tilton and Blynhym apricot, apple dandy and some kind of plout 3 different kinds.
I also successfully grafted the king flavored plout to my nectarine, satsuma plum, santa rosa plum unknown plum and green gage plum. I find it so easy to graft the plout to so many varieties and vice versa.
I'll show pictures later.