status_model.js

Status = Backbone.Model.extend({
  initialize: function() {
    this.id = this.attributes._id;
  }
});

StatusCollection = Backbone.Collection.extend({
  model: Status,
  url: '/social/twitter/status',

  comparator: function(status) {
    return status.get('created_at');
  }
});

Statuses = new StatusCollection;

twitter_model.js

Twitter = Status.extend({
  initialize: function() {
  }
})

TwitterCollection = StatusCollection.extend({
  model: Twitter,
  url: '/social/twitter/status',

});

Tweets = new TwitterCollection;