For developing EMF models the option "Create Dynamic Instance" can be very usefull. When you have a EMF meta model and you want to create a first test instance of the meta model the option "Create Dynamic Instance"can be used see the screenshot...
For create Dynamic Instance do a right click on the RootObject of your model that you would want to instantiate. The screen shot bellow shows the editor for editing a EMF based model dynamic in eclipse as XMI.
More details on dynamic instantiation in EMF: