[weinzierl]

CAcert has a system in place that is close to what you described[1]. Basically already verified users check the identity documents of new users and vouch for their authenticity. Their "Assurer Handbook"[2] is an interesting read. When I became an assurer a few years ago the person that trained me also took their task very seriously and I learned a ton about how to check identity documents for forgeries. That alone made it worth it.

Since we have Let's Encrypt I'm not entirely sure what CAcert's place and purpose is, but I think with an existing network of trusted people they are in an ideal position to pivot into a decentralized online identity system.

Mark Shuttleworth's Web of Trust similarly had so called Thawte Notaries but I think it was discontinued a few years ago.

[1] http://wiki.cacert.org/FAQ/AssuringPeople

[2] http://wiki.cacert.org/AssuranceHandbook2