Using the rewarding.app one can make their own downvote curation trail.
However, the problem of this is which account to trail? I don't recommend trailing the accounts that go after the big guys for grey area things like reward disagreement. I think making an account that goes after obvious abuse only which can be trailed will be good.
Another idea is making a proposal to power up some of that Hive in the @steem.dao account and just delegate it to the cleaners. It can always be burnt or powered down later. In fact a proposal to start funding a decentralized Mr.delegation may be an interesting idea.
All reasonable ideas. Let's see what hivewatchers can come up with.