I like the way you think Dan!
... the "donate x amount of the rewards to the Steem fund" idea is good - but is that not like the existing Promote option? Tho getting a badge and support for using Promote would be good as I feel with Promote button is currently unclear if it is worth using! making Promote a clear winning option would be excellent for the platform and take some money back from the vote bots perhaps!
Upvoted and resteemed :D