I've never been on a cruise and being prone to motion (think car and sea sick) probably never will. But, I still like to imagine what type of clothing I'd take on a cruise to a tropical isle.
Ever since I saw one of these versatile dresses on tv when I was small, I thought they would be great for travelling but could never decide on a colour.
The ones I've seen are called mai tai dresses and they are a stretchy knit material with a giant belt which allows you to loop and wrap the dress in literally hundreds of different ways.
It's not the height of fashion or anything, but looks like a simple basic dress that travels well.
Here is another one with an uneven hem-line from a different company:
I still like this dress, but cannot imagine just wearing the same colour over and over again. People would know it's the same dress.
The other hindrance factor is the cost - they are quite expensive, around $300! basically for a giant sized piece of knit fabric with super long straps attached. You could probably make one. Even if you paid $20/metre, how much fabric would you need? maybe 5 metres at the very most = $100. And the fabric would probably cost half that or even less.