Dear Pineapple Princess,
There are these types of cruises, however all the procedures are done on land at a port of call. Typically these cruises are group charters and are not well advertized except by those on the wait lists at cosmetic surgery clinics. (i.e. if you have expressed intrest in traveling to buenos aries for some lipo they will let you know of the recovery charter). Of course the downside to this is you still have to make pre-op consulatatin with the physician and you have to decide if you want a foreign dr operating on you.
The way it typicall works is you embark at one port spend a a couple of days on the ship then arrive at the surgery center port. Folks disembark for their surgeries and reboard typically in a few days (when you have been cleared by the surgeon.) Then you spend 7 to 10 days on the ship. By the way the only instances that I have heard of are the "smaller ships" that only house 200 to 300 passengers. From my understanding at the surgery clinic I was looking into in thailand they schedule these on an bi annual basis according to procedures. (they wait till they have 40 lipos for example)
The price was also pretty expensive. the cost of surgery plus about $500 a day for the cruise (supposedly there are dr. and nurses on the ship for post op treatment). I was looking at lipo and a chin lift which normally over there would run about 6500 usd and to ad the "cruise" made it about 14000 usd
Just google search foreign liposuction and try the japan and thiland surgeons. So far I have not been able to find any in the caribbean area.