It's not on advanced/rules at least: http://test.dwagn.org/card/options/Accountless_User
fixed. there was just something funny with the toggle data for that one *accountable rule.
note that there are three things that have to happen for that link to show: (1) there must not already be an account, (2) the card must be accountable, and (3) the user must have permission to add the *account card.