JavaScript code:

// Define an event aggregator with request-response and command behavior
SuperVent = Marionette.EventAggregator.extend({

    constructor: function(){

        // And here's why it's a Super Vent
        this.commands = new Backbone.Wreqr.Commands();
        this.reqres = new Backbone.Wreqr.RequestResponse();

        // Call the superclass constructor to get event binder mixed in
        Marionette.EventAggregator.prototype.constructor.apply(this, arguments);
    }

});

// In the master model's "initialize" method - this module includes a `vent` supervent instance as a dependency
vent.reqres.addHandler("wizard:model:master", function () {
    return this;
}, this); // this last argument sets the callback context

// Now from any other module that has a reference to the same vent, you can do this:
var master = vent.reqres.request("wizard:model:master");