I like the chain saw idea, don't want to limit your nanners growth
but on the serious side
a Dwarf Cavendish should only reach a height of about 6-8 feet. in a pot, I'ld take a foot give or take 6 inches off of that. I have one that has been in a pot, graduating to a 25 gal. pot over the last year. Big pot= big heavy to move, but it seems to be very happy. I live in zone 5, N. Illinois,
