I've thought about it before and one way i think is what you said to keep in a small size container. Also i think if you always keep it on a light cycle of 12/12 it might just stay very small. maybe topping it a few times also. I don't really know but it would be interesting to try.
I just decided i was gonna do it, i've been interested for a while since I started trying to grow bonsai trees, i figured i'd combine the two, actually since i found this picture...which im not sure is real or not, i'd like to think...yesss. Anyway im gonna germinate them and put them on 12/12 very early (i might let them grow 24 hrs a day for a week or so). Im gonna put them in a small area with 1 or 2, 42w 2700k cfls, very close. Im gonna start with 4 or 5 seeds ill keep them all in very small containers and 1 or 2 i will try topping, also i am going to try tying down/wiring the branches as you would traditionally do in bonsai. We'll see how it goes. Ill make a thread somewhere and post it back in here.
Sorry for kind of hijacking your idea, but i really had been thinking about it for a while...Are you doing it becasue you need to grow in a small area? Anyway thanks for giving me the motivation to do it without knowing,haha.
I found this picture on some bonsai site a few months ago....