lets say i have a small app to store and manage contact details (an address book) i have multiple users that can login and they each have their own collection of contacts... ref: http://stackoverflow.com/questions/7385629/backbone-js-complex-views-combining-multiple-models

dynamic model

var model = new Backbone.Model();
model.set({contacts: new ContactsModel(), users: new UsersModel()});
var view = new GridView({model: model});

var contacts = new ContactsModel();
var users = new UsersModel();
var view = new GridView({model: contacts, users: users})