Can I disable the control panel? Is it possible? I have a situation where a client needs the production site to be completely shut down and void of content updates. They do all of their content management on a staging site, then publish the database when changes are approved.
Good call Brad! Not sure why that didn't occur to me :)

Here's how that's done: 

# Kill admin access
RewriteCond %{REQUEST_URI} ^(.*)/admin
RewriteRule ^(.*)$ - [F,L]