Workbench Moderation - Admin Preview - Show Current Revision in Front-End
It sounds like you want Page Preview.


  Page Preview is a low-impact alternative to Drupal's core node preview
  functionality.
  
  Why would I need this?
  
  Drupal's regular node add/edit form provides a "Preview" button that
  allows you to see what your node content will look like after all of
  the input filters are applied, without having to first save the node.
  However, it doesn't allow you to see what the entire node will look
  like within the context of a fully rendered page