If you do a search for 'interline travel' on the web, you will find plenty. The industry tends to be dominated by American companies selling cruises, but there are good deals around. Ticket [flight] prices tend to be dictated by the particular greements that your airline has with others. Hotel/cruise deals are more generalised. Some of the best deals on accomodation can be had by dealing direct with a hotel and asking for their airline rate.