OK, I'm perhaps too excited about this, but I've just discovered that what appears to be Apple's OpenDirectory (sans GUI, of course) exists in the non-Server version. While poking around, I came across /etc/openldap, which has configs and schema files for, among other things, NetInfo!
WARNING: if you don't have the firewall turned on, others could connect to your LDAP server and view your NetInfo information.
With two simple tweaks, I had LDAP running, and access to it with an LDAP browser:
/var/db/netinfo/network.nidbchange it to:
/var/db/netinfo/local.nidb
LDAPSERVER=-YES-
% sudo /System/Library/StartupItems/LDAP/LDAP startIt will start the LDAP server, and you can access it, with a blank base DN and anonymous bind (ie. no User DN/password) This is a flaw, IMO, but if you have the firewall turned on, you're good. I'm looking into how to require authentication, and hopefully will be able to enable SSL, as well. If you're looking for a decent Java-based LDAP browser, check out this one, from Jarek Gawor.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020902075936558