Grafting is awesome-- and sometimes you can get some really interesting results. As we see around town with some of the ornamental cherry trees, which are part pink and part deep red-- with different foliage, even, on the same root stock.
I wanna say there's actually something now called "fruit salad trees," but don't quote me on that.
Yeah, "fruit cocktail" trees, featuring a variety of either apples and pears or of peaches, plums, nectarines and apricots.