excellent point about tangled roots. nothing worse than hearing that horrible (yet affirming) crunching sound of roots being torn apart. I'd hate to imagine that happening to two or more plants at the same time.

also...if sharing containers, even if you rotate the containers for even light distribution, it would seem that the inside of each should theoretically suffer from light loss.

I would love to see a picture from a grower who has pulled off growing two or more to a container, either by training, bending, or whatever...