Thanks Falko! I changed the /etc/selinux/config to read "disabled" and rebooted. Now I can sign in on both runlevel 3 and runlevel 5. I think my machine is now FULLY configured for RAID, but I haven't done the testing for a failed disk yet. I may wait a bit and have a beer first ... I don't want to ruin the moment!
Any advice on why SELinux nixed my log on would be appreciated. I guess I should also put a book about SELinux on my reading list!