For RoD to work in that way, etc.. they need to release an API or soemthing similar, for developers to be able to make calls to, etc... which doesnt appear the case.
Even stuff like netflix right now, for wmc and XMBC, only really allows the pulling of QUEUES from them.. you can use the app to set that up.. and when you launch something, it actualy launches a BROWSER, using the queue to call the one video from the 'regular' website.