Also just out of Curiosity are you the Bonsaiboy from the website that sells the Bonsai Tree's Tools and Pots and things? or just someone that came up with that name separately
No, I am not that same bonsaiboy. Its just a coincidence that the names are the same.
However I do get where you coming from with the thick trunk an all, I think maybe if I got another F Benjamina I would try that method but right now I just want to try cuttings even tho it might take a long time to get a thick trunk.
What you could do is get a cutting from the ficus, and once you have it rooted and all, you could then proceed with cutting the tree down.