They can be trained, but very few get that tall. Yes they will go dormant; it's required as part of their growth. Do not cut it back for winter. Not knowing which one you have, I can't tell about protecting in winter.
The only true climbing fuchsia is Lady Boothby, here in the UK, when well feed during the growing season, it can get to 6ft plus. It is hardy and I cut mine back to 3ft every Spring after all risk of frost has gone. - Kath :)
