The "Marseyverse" exists. It really only has individual subreddit-websites. Each website is a fork of Ruqqus code (which itself was a failed-reddit clone that forked reddit's code) Examples would be
rdrama.net watchpeopledie.tv themotte.org ovarit.com
All full-reddit clones that I know of have failed miserably. And many reddit communities have tried establishing off-sites and failed. The factors for success seem to be:
1. The communities were banned or hampered on reddit 2. The communities have a unique culture 3. Some people in the community take on the responsibility for developing/maintaining the offsite 4. The users of the community donate money to keep everything running (a la SomethingAwful)