I had discovered the solution to ldap preventing a FC7 system from booting months ago and I thought I had written it down but when I upgraded on of those junk heap Dell Optiplex 320's that I was fighting with a few months ago from Debian to Fedora Core it reared it's ugly head again. The boot process stops at Starting System Message Bus and sits there for a very long time. It eventually times out but not before your hair has turned grey.
To fix it you have two options:
Remove any mention of ldap /etc/from nsswitch.conf
or
change
bind_policy hard
to
bind_policy soft
in ldap.conf
