http://httpd.apache.org/docs/trunk/mod/mod_authn_core.html#authtype talks about "AuthType None", and has an awesome example of exactly what I need to do - unfortunately, it appears to be new to 2.3/2.4. Is there any equivalent feature in 2.2?
The authentication type None disables
authentication. When authentication is
enabled, it is normally inherited by
each subsequent configuration section,
unless a different authentication type
is specified. If no authentication is
desired for a subsection of an
authenticated section, the
authentication type None may be used;
in the following example, clients may
access the /www/docs/public directory
without authenticating:
<Directory /www/docs>
AuthType Basic
AuthName Documents
AuthBasicProvider file
AuthUserFile /usr/local/apache/passwd/passwords
Require valid-user
</Directory>
<Directory /www/docs/public>
AuthType None
Require all granted
</Directory>