I haven't run across or know of any tutorials on this exact problem, but I think you're right that you'll end up doing a lot of the synchronization yourself.
You might check out PubNub and other messaging services. PubNub is a stackmob partner product that can be added in their marketplace.
That would provide for a component to handle transporting messages and state information between your document editors.
You might check out PubNub and other messaging services. PubNub is a stackmob partner product that can be added in their marketplace. That would provide for a component to handle transporting messages and state information between your document editors.