Interesting. I am curious if this would work in colder zones as from what I understand the points where the branches are grafted are more susceptible to winter kill? On the plus side, you wouldn't need another tree for cross pollination.

Top grafting stone fruits works pretty good here, have some trees with many tender cultivars on top,..like Green Gage and Mirabelle de Nancy and Prune Plums. At one time I had a apple tree with about 15 different varieties top grafted, it lasted about 10 years when fireblight took hold of and died. The root stock cam up again, then I grafted one of my pink flowering crab apple seedling [ornamental]. Back to a healthy tree, about 12 foot tall now.

I find, too much grafting on one tree has a much higher chance
of getting this disease.

I just thought the blossoms looked awesome! :)

Ginny