You are not alone in your request. We are currently working on creating plugins that will provide what you requested. I believe the phpnuke plugin is almost complete:
As far as CMS's go this topic might help:
I have currently switched a decent amount of the pages I make to joomla, www.joomla.com
. I found that for the average user is it simple and easy.
Drupal might also be something to look at. www.drupal.org