You try to paint a picture where every mod author and even you just have to endure these dark times without anything YOU, yes, specifically YOU can do. However, all it takes is some balls. Create a moderating team who's only job is to verify if a mod, or it's assets got stolen. Screen caps work. In game recorded footage works. If by chance the "thief" has a name on the Nexus, IP-ban the living **** out of him forever. If an author "turns on the dark side" by having his mod be removed to sell them on Steam, do the same. Those who turn their back on us don't deserve to be here. They are part of the problem. Implementing a system where totally new registered users cannot download (or have their downloading abilities restricted in some way) is also an option. Steam already does this: new accounts cannot sell items, or even chat or communicate in any way as long as they haven't spent at least 5€ on the Steam platform. You need to do something similar. Be that a one-time paid membership, or a credit system. That way you can stop the thievery that is going on. Because believe me it will happen. People will realize the easiest way to grab cash is to just download a mod, repackage it and put it on Steam. If the original author is unaware of this in that 1 week time period then it's too late to do anything. They (including Valve, including Bethesda, and DLC maker wannabes) have started this but WE have to stop this.