Bananavilla

I think Gabe:edit - (Frank) is right on the money. It is simply power in numbers when growing in a non-ideal climate. I also find that for me the best success if you have a plant about 1-2 feet below it's fruiting height when going into winter.
Southergrower is doing a little experiment with 3 trunks on a clump of Raja Puri to see first hand the effect of multiple stalks fruiting from one corm. I personally think it would work fine if you have the space for it. They are not going to fruit at the exact same time.
Joe, how about leave them in three's, then when the first one of the season blooms - cut the other 2 off and allow a new pup to grow for the following season?
I also have not had that much success moving large established trunk as far as going on to fruit the following season. I think you'd be better off growing them in large pots the first season and planting them out first thing in spring.
Mike