The Silja Line ferries I have taken between Sweden and Turku, Finland in the early '80s were indeed pretty fancy.
I don't know whether that old Greek liner, the Lindos, that around 1971 used to run weekly between Ancona, Italy to Haifa, Israel, via Corfu, Athens, Rhodes, Limasol and Famagusta can be considered as a ferry or as sort of a cruise. I used it as a real cheap means of travel, i.e as a ferry.
Though she had a swimming pool, the meals and accommodation were rather spartan: cabins were shared accommodation: 4 people, bunk bed style.
Food was basic Greek fare; lots of black olives, but it was cheap:
Ancona-Haifa was $78 for the 3.5-day voyage inc. bed, shower and 3 meals/day. I paid an extra $15 for my motor bike.
Haifa-Athens, for example, this 2.5 day voyage cost only $36, again shared cabin + 3 meals/day.
Does anybody know what happened to this Lindos and how long this service operated?