I was thinking, maybe there could be a new rank that can moderate how the moderators do their job, yes, that is what the ops do, but sometimes they are not on, and you don't want to just make someone op because you need someone to inspect the moderators, that would be giving them extra commands they might abuse. But with this rank, maybe it could be that you can use /vanish and mods can't see you when you use it so you can see what they are doing. And they don't have to have the privilege to fly, but that would help because moderators can fly.
So, what commands they get is /tp and /vanish. And you could make the /tp command only be able to tp to mods for the new rank, and the /vanish command, it could be that mods- can't see you.
They could report back to the admins and ops in a new forum only available to SMP ops+ and ofc, the new rank.
You don't have to take this in, I just think it will be nice to have and it could ease your job a bit more, you could pick specific people or open applications, I would say picking specific people would be the best choice, but again, it is all your choices, nick and relkeb.