Automate your WordPress Editorial Workflow with Oasis Workflow.
Clones an existing site into a new one in a multisite installation : copies all posts, settings and files
Creates functionality to duplicate any and all post types, including taxonomies & custom fields.
Create the next version of your post while preserving its already online version.
Copies/Duplicates Posts, Pages, and Custom Post Types with just one click.
Gives you the ability to clone posts, and replace posts. Together, you have a very powerful tool for a fork/merge editing model.