The modder in question for this case is not above placing DRM within his paid mods to prevent free distribution. So I'm skeptical of any system of monetization not immediately succumbing to malicious compliance.
Mods are by the community, for the community. If your mod has enough significance that you believe it is worth monetizing - create your own game with the endless amount of tools available with that hallmark feature. (Or actually talk to the devs to work out an official arrangement rather than being a hardass and witnessing the consequences of your arrogance)