My implementation of nested models for Backbone.js. Read more at http://codrspace.com/vote539/nested-models-and-collections-in-backbone-js/

backbone-forward.js

Backbone.Model.prototype.forward = function (attribute, subModel, options) {
  var self = this; // parent model
	var property = (options && options.property) ?
		options.property : attribute;
	self[property] = subModel; // save the subModel in the specified property
	subModel.set(self.get(attribute)); // add any existing data to the subModel
	self.on("change:" + attribute, function(model, value, options){
		subModel.set(value, options);
	});

	// Implement here all methods on the child that you need to trigger change
	// events up in the rest of the model tree.
	// 
	// For example, here is how you could implement the "add" function for
	// Backbone.Collection.
	subModel.add = function (model, options) {
		var collection = _.clone(self.get(attribute));
		collection.push(model.attributes);
		self.set(attribute, collection);
	};
};