FYI, there is now a report of such a recovery:
https://old.reddit.com/r/Bitwarden/comments/1k8gzy3/cannot_login_to_my_bitwarden_account/mp6sxls/
Unfortunately, this user did not explain what kind of information (if any) that they were asked to provide for purposes of verifying their identity. Frankly, the impression I get from the descriptions in that Reddit thread is that it was sufficient to provide the original email address.
The only limitation to account access seems to have been that Customer Support disabled the user’s New Device Verification for “only” 24 hours.