There is a company in Australia that produces and sells a series of trees that can bear up to 6 different kinds of fruit. Seriously...

According to the Fruit Salad Tree Companies website:

A Fruit Salad Tree bears up to 6 DIFFERENT FRUITS all on the ONE TREE. They are multi-grafted trees with different fruits from the same “family” and all the fruits retain their own characteristics e.g. flavour, appearance and ripening times.

So, while you won't get a banana and apple growing together, you will see an orange and lime, or a plum and peach on the same tree. They have 4 different kinds of trees: Citrus, Stone, Apples, and Nashis. Hit their website here, and if you order one, make sure you let us know about it!