...
In the end, it sounds like our best option may be to ask the DuraCloud Team to create a way to turn off the "auto-delete" option of the DuraCloud Sync Tool. Bill Branan seemed open to this idea, and is investigating it (from the sounds of it, he thought it'd be a worthwhile and relatively easy hopefully not too difficult of a change).
Here's a basic example future DSpace/DuraCloud interaction workflow, that may allow us to perform a "trickle" synchronization of content:
...