Re: Is there a ferry to Lisbon from either Rome or Genoa?
The answer to this question is No and is should be No. If you look carefully at a map you will see that Lisbon is an awful long trip from Rome or Genoa. About the only sea way to get to Lisbon from Italy would be to book a regular cruise ship, and it will be a rare cruise that covers both of these ports on a single voyage. The best way to Lisbon from Rome would be to fly.
This may be too late Maggie, but Celebrity in 2000 had a reposition cruise one way from Amsterdam to Genoa. It included Paris, Brugee, Lisbon, Sintra, Barceloa, Malaga, Monaco, Rome, Florence and you disembarked at Genoa. Check out their September itineraries for last minute fairs.