In a small saucepan, combine pineapple juice and honey and simmer until liquid reduces (to ¾th of a cup), about 5 minutes. In a medium bowl, whisk egg yolks well. Add half of egg yolks into the saucepan in a slow stream, stirring constantly. Add the rest of the yolks, stir. Cook over low heat, stirring frequently, until mixture thickens (about 10 minutes).

Transfer mixture to a large bowl and beat with an electric mixer until the mousse has cooled and is very thick. Scoop out the firmed up coconut milk from one can and place in a medium bowl. Add ½ teaspoon vanilla extract. Beat with electric mixer until soft peaks form and it takes on a "whipped" appearance. Add rum to coconut whipped cream and beat until combined.

Fold coconut whipped cream into mousse. Cover and chill mousse for at least two hours.

Before serving, open second can of coconut milk, remove solid and place in bowl, add remaining ½ teaspoon of vanilla, and whip with electric mixer. When ready to serve mousse, top with coconut whipped cream. Sprinkle with shredded coconut if desired.