What do you all think of invite only sub-steems? In which people can organize around specific ideas. This could work for community projects, like community gardening ideas. But it can even be taken to something even more abstract, such as writing a comedy script. Invite a bunch of freelance writers into the substeem and then they post jokes and the most upvoted payouts immediately. 

The biggest concern I see is how the rewards are distributed within a private channel, as it can't include the rest of steem. 

Just a thought