Need Help! I planted a group of banana trees this spring but need to move them for a patio addition. Can I dig them up and store them till spring? If so how short should I cut them back? The shortest is around 8', the tallest is around 12'. Any and all help will be appreciated.

I cut mine all the way to the ground and cover them with 4-6 inches of mulch or compost. I have a friend who thins his to just 2-3 stalks each year and leaves 3-4 foot above ground in the winter. He wraps these trunks heavily. Mine always freeze to the ground.
If you move them now you take a chance on them freezing or rotting. Try transplanting some and try holding some over in an area where they are protected from the weather. Get a large bucket and put the root ball in there. This would be one of the only times I would consider using peat moss to store them in.