Feature Request: id by e-mail, twitter, reddit, etc..

I had sent a colleague an invite for Keybase.io. I knew that he had signed up, and I knew his e-mail address. But when I attempted to do a keybase id for his e-mail I receive an:
error: missing or invalid input (error #100)

Luckily I knew what handle he registered under so I was able to find him that way.

Would it be possible to a keybase id based on e-mail, twitter, reddit, or any of the other verification checks that are done in addition to their handle?

The issue does not name files, tests, or entry points. Start by reviewing the existing Keybase ID lookup flow and how verified email and social proofs are represented, then clarify which identifiers and privacy rules are supported. Done means the requested identifiers work consistently with the existing handle lookup and have coverage for valid and invalid inputs.

Written by the indexing model from the issue text.