Just to add one more touch;
I was able to find an ldap.bak in the still existing openldap-data directory, copy it over to data/ldap and chmod 440, rerun /opt/zimbra/libexec/zmsetup.pl and it worked like a charm.
At first I thought I b0rked my install, by trying to go from 5.0.20 > 6.0.0; when it failed, I figured that was the cause of 6.0.3 breaking.
I hope that helps someone out there
