Ben Albahari wrote to tell us about TakeOnIt, which is trying to build a database of expert opinions. This looks very similar to the data that would be required to locate the Correct Contrarian Cluster - though currently they're building the expert database collaboratively, using quotes, rather than by directly polling the experts on standard topics. Searching for "many worlds" and "zombies" didn't turn up anything as yet; "God" was more productive.
The site is open to the public, you can help catalog expert opinions, and Ben says they're happy to export the data for the use of anyone interested in this research area.
Having this kind of database in standardized form is critical for assessing the track records of experts. TakeOnIt is aware of this.