It's a really interesting topic, but I think trying to find people who have been defrauded would be difficult.

If someone stole my miles, I would probably contact NW first. But NW would probably say, we can't help you. There might be a record of this at NW, there might not. (Their TOC might say right out that NW isn't responsible, so the CSR might not even bother going too far up the chain.)
My next step is my local DAs office or AGs office or police. But they would probably only look at the stated value of miles if that. I doubt they have files of FF miles stolen. You'd probably have to get people who just remember, but the chances of them remembering the actual name of the case, even if they remember the situation, I don't imagine would be good.

Then again, where there's a will, there's a way. Good luck.