Many of the luxury cruise lines include all the drinks you want for the entire cruise and I read where Royal Caribbean may have a program that includes all-you-can drink from their cocktail menu for a flat fee per day.
Most of the cruise lines see the sale of cocktails as a major profit center, so the days of cheap drinks are over (with some exceptions).
Interested in Europe? Here in the UK we sell tour operator cruises on an 'all inclusive' basis, but they would fly in and out of here and sail from Palma Majorca.
Pleased to offer any help if necessary!