If any of this comes to fruiting please PM me, since I would like to try it out personally.
I'm not sure I am following what you are saying. Do you mean a user can upload a file, then deposit some coins to make it available to download for free until the funds run out?
Yes, exactly. A similar thing can be done where the user uploads a torrent file, then your service leeches it, and then seeds it until their funds run out. I remember there being a service that did exactly this a couple of years ago, but I cannot remember its name. Their business model ran something like charging a small amount per hour of seeding the torrent and then a more significant amount for the actual data upload. I am sure you could use a CLI-based torrent client to make this easier, but of course that is just a suggestion. If anyone who reads this remembers the name of the old service that provided/may still provide this that would be nice too.