Apparently somebody at WeRelate got a big list of all the surnames on Ancestry (not all real), and clustered them automatically by Soundex or similar, and put the list out so that users could manually delink the ones that shouldn't be linked. But that process hasn't got very far yet.
Easier said than done. Really it needs a country code. When I looked at it, I didn't bother getting a username, because although I would have unlinked names in an English context, I wasn't going to say they were never linked in America.