The problem with that approach is that the plant will eventually become rootbound, and then you won't be able to divide it or get it out of the ground. I have a friend who had a stainless barrel about that size that he used to contain his bamboo. It worked for a few years, but now he has a fairly good size plant that is unhealthy looking and occasionally puts out sad, partially leaved culms. Since the container, filled, weighs at least 600 pounds, the only way to deal with it is to destroy the plant, cut through the rhizomes repeatedly, and pry and dig the remains out.