Impressive story, despite the Django and EC2 plugs.
Of course this suggests a start-up project: a business service that does crowdsourcing. The service would be customized for one task and would have various forms of cheat detection (e.g., CAPTCHAs, user profiling, meta-moderation and maybe some secret sauce).
Mechanical Turk is fine in many cases, but this story shows sometimes it's better to roll your own (or have somebody else roll it for you).