AFAIK, you can create a community where anyone can post, the community aspect just allows for moderation (e.g. removal of posts that aren't really related to the community topic). For a community of this sort, it would probably make sense to give the owner key to several people, just to ensure it's not lost.
Regarding your last question, someone did create an account of that sort, but I forget it's name. Edit: at least I think they did...