I'd like to extend the 'DMV' / existing government licencing system with a standard digital signature (PKI); which would be applied to the OpenPGP / X.509 / etc public key you provide asserting "I own this" in a standard key-party manor (send the signature encrypted so that only the private key can decode it).

It would also be useful if you could provide multiple keys and associate them with one or more databases: 'full identity' (public listing with name) or key ages (probably 18, 21, and whatever social security/etc ages are).

The latter thing would allow for sites that require 'adult' access without forcing them to request credit cards (not always of age) or personal ID. It might not even be part of the standard flow, but merely as part of establishing an adult is involved if there's a dispute.

PS: 'adult' also implies 'able to sign contract' (such as accept Terms of Service). Financial sites would obviously require the full legal name key.