After a few days of research, I've decided I need to start asking around for tips, or else this thing will never get done.
Long story short, my country's WH40k community is somewhat falling apart, because we can't properly manage our forum. It's running on some old clunky engine (Dragonfly) and at this point even the admin doesn't know how to do as little as move it to another place, never mind update it or add new features. We need a completely new engine and I've been delegated to choose, install and admin it.
We really, REALLY, need an infraction system like the one used on these here very fine forums. The bare minimum we need is:
-A very clear and visible "USER WAS WARNED FOR THIS POST" note next to the infracted post
-Infraction posts that accumulate and then automatically expire one by one
-An automatic tempban for people who accumulate enough infraction posts
Unfortunately, Vanilla OS doesn't offer a plugin like this (the free Warnings plugin is very limited), phpBB seems to have one that hasn't been updated for ten years and vBulletin is at this moment outside our price range (and even then I'm not sure if their infraction system works well). Needless to say, we're a medium sized non-commercial hobby community, unable to pay a monthly fee, especially in the Vanilla Cloud range.
Can anybody recommend a free or cheap one-time payment forum engine with this functionality?