Your first solution is possible, AngularJS allow to change the start/end symbols of text interpolation like this:
appModule.config(function($interpolateProvider) {
$interpolateProvider.startSymbol('{[{');
$interpolateProvider.endSymbol('}]}');
});
Then you could use it in your template:
<div>{[{message}]}</div>
Also see: $interpolateProvider documentation
Hope this helps.