Dropship hack was immediately rendered useless by Dropbox by requiring that a random part of the file be uploaded, even if Dropbox already has many copies of the file in their system.
So use the Dropbox as the golden copy/SHA reference, and fetch the file from peers over Bittorrent.
DB is always going to be able to be used like a resilient tracker/datasource, and DB devs can only put so many walls in the way of using it like that before it starts to hinder your "average" user.
Example: Get magnet hash, get data from Bittorrent swarm, and then fetch from both swarm and public copies available via Dropbox. Verify against Dropbox copy if necessary.
DB is always going to be able to be used like a resilient tracker/datasource, and DB devs can only put so many walls in the way of using it like that before it starts to hinder your "average" user.
Example: Get magnet hash, get data from Bittorrent swarm, and then fetch from both swarm and public copies available via Dropbox. Verify against Dropbox copy if necessary.