Zen Underwater has confirmed the recommendation for the Olympus 7-14mm:
Nauticam N85 to N120 60mm Port Adaptor, p/n 36204
Nauticam Extension Ring 20 with Lock, p/n 21120
Zen Underwater DP-170-N120
Due to the large diameter of the lens, it's designed so that the 60mm port adaptor is attached to the housing first, then the lens, then the DP-170-N120 with the 20mm extension. I've attached some photos of this setup.
Has anyone had this setup in the water yet? Is there an existing zoom gear for this setup now or is a new gear required? I am getting a bad case of GAS.