A properly exposed image on medium speed 120 film gives you lots of scope to crop your portrait shot into any shape you like. Or you could find yourself a Tele Rollei with its 135 mm (I think) taking lens, use a Mamiya TLR with a 150 mm lens (or thereabouts) or find a Rollei SL66 and 150 mm lens. The first option is the most practical. Many great portraits have been done on Rollei TLR's.
Have fun.

Morry Katz, Lethbridge, Canada