I don't have a lot of space to grow, so when I get a new strain I usually take very small clone and flower it to see if I want to dedicate precious square footage to a real grow with it. I think this one is about done getting taller now, but still has a few weeks left. I'd say 3" is probably the smallest I've grown to harvest without topping or training.
I have a 2 year old Coast Redwood(the 300 footers) in a bonsai pot standing a whopping 2 inches tall, so I imagine that if somebody really put their mind to it they could make a seriously tiny bud.