Well... It is not that hard to find one. The most abused signature campaigns are those in Bounty section. Why not try that? You may find multiple accounts enrolled in the same campaign which is against the rules. Those signature campaigns who pay in BTC have strict managers having high standards which farmed accounts don't have.
That is absolutely the worst section on bitcointalk, and though I have no data, I agree with you--just from glancing at what's posted there. Most applicants are noobs, and there are many, many of them. The probability of all these noobs NOT being alt accounts and NOT abusing those bounties has got to be infinitesimal. That script sounds very interesting, though I won't claim to understand how you do what you do.
I would be very interested to see what the results are. I do think that the campaigns that are in the Services section--the ones which pay in bitcoin--are pretty well-run and have fewer abusers (though they're certainly not free of shitposters). Good luck on your project, dude.