Have you ever tried to fuse the trunks of trees, and if not why not? It is great fun to try out different species and so far I have had good success with Ficus as they seem very adapt at fusing trunks particularly Ficus benjamina.
There are some other trunk fusion enthusiasts and here are a few links to some of the most recent posts I have found whilst browing on the subject:
Ficus Bonsai Trunk Fusing Experiment by Marin Homestead
Ficus fusion project by Shane Martin
Fusion Bonsai by Greg Wentzel
Tad’s Ripple at Fuku Bonsai
Advanced Grafting of Figs by Jerry “Bonsaihunk”Meislik
Fused Trident trunk by William Feldman on Internet Bonsai Club