Pretty much any blueberry bushes can make a hedge. Thats how they are planted at the farms around here, in rows thick like hedges.

Tallest blueberry bushes you can get are Rabbiteye, they can get up to 20 foot tall. Those are more southern. Highbush varieties can be around 4-6 feet tall, some can get around 12 feet tall. Some of those can grow more Northern.

Looking at mine I'd say they don't grow thick enough to make a privacy hedge. They are all leaning to the east for the morning sun. And looking at mine i think I'd plant them about 2 feet apart for a hedge. From my memory; Jersey grows 7 feet tall and my Sweatheart has been 5 1/2 feet tall for two years now. Those are the two I'd consider, but I don't know the Rabbiteye's; but I think they're a southern blueberry.