To my knowledge, no, but it's mostly due to the fact that such a script would involve a compete rewrite of a vast majority of all the default systems. This would be wildly incompatible with pretty much any plugin that changes much about the engine, not to mention really time consuming to make, bug-check, and maintain. As a result, you'd need any other plugin for your game to be either custom built, or altered to work with your co-op system, which in many cases is not a simple task. Not to mention that any updates to the base engine will also probably cause several issues with it, depending on what was changed, so you'd likely have to develop the plugin on whatever version is out when development is started, and then you'd have to stick with that version of the engine for the rest of the project.
