Yeah so essentially what you want is to do is create an equals template helper, here are a couple resources from the past:
And the benchpress docs
Has this been attempted? Basically, I'd like to enable multiple users to work on a single post at once.
I doubt this has been explored at all, since this being a forum software in general and not something like Google Docs or any other collaborative software out there in the wild. I would like to see it as something Discourse has with there "Wiki Posts" but I won't suspect it to be even a low priority for the devs.