There is no need for $.getJSON, a JSONP model or any other code adoption.
This actually works out of the box:
new sap.ui.model.json.JSONModel("http://pipes.yahoo.com/pipes/pipe.run?_id=eb8dcd1d84e4aa323378ce219683878a&_render=json&_callback=?");
Live example here: http://jsbin.com/babiqoze/1/edit?html,output
The important thing is that you set the value of the callback parameter to "?" so that jQuery detects it and handles it as an JSONP request. http://api.jquery.com/jquery.getjson/#jsonp