And I'm an idiot. In my post above I had typed the following:
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}
Too bad that isn't actually what I had typed in the httpd.conf file. While trying other things I discovered I had not only forgot to load mod_rewrite but also added an extra S and incorrectly typed.
RewriteRule (.*) https://%{HTTPS_HOST}%{REQUEST_URI}
Oh well, lesson learned. Hopefully this helps someone.