If you are willing to consider other cruise lines, Holland America has an interesting itinerary that they run once each year.
I did a 25 day cruise this past Summer that included 2 stops in Greenland, 6 stops in Iceland, 1 day cruising Prince Christian Sound, multiple stops in Nova Scotia and Newfoundland, 2 stops in Maine (Portland and Bar Harbor), and 1 day at the island of Saint Pierre. The ship (ZAANDAM) did a complete circumnavigation of Iceland.
This trip required no international flights. The cruise started and ended in Boston. As I already mentioned, this itinerary is only offered by HAL once each year. Hope this helps.