In St Thomas I visited St Thomas Synagogue(Charlotte Amalie St). This synagogue is the oldest in the contiguous United States! When marrying at the synagogue, the signing of the ketubah and the bedekken are also included in the services.
Aren't the dark mahogany woods and blue cushions on the benches perfect for a Caribbean wedding? What makes it even more island...the sand floors! You can read more about the theories of the sand floors here.
For information on getting married at this hystoric synagogue, email mina.synagogue{at}gmail.com
For great information on the US Virgin Islands, go to VisitUSVI.com. Its a great resource for gathering information on having a destination wedding on St Thomas or St John.