hi @bhuz. I'm a little late to this post, but I just read about it on @clains's witness report. Great idea! I am really appreciative of any 'whales' that are actively trying to reward more underpaid 'minnows' that are providing great contributions to the community. I think that this is one of the most important issues facing Steemit right now. We are doing a great job recruiting a lot of great people, but keeping them here is even more important.
As far as rules to select eligible contributors, I would recommend allowing people to submit things like people have been doing on this post. You could also recruit a few people to hunt for good content and report back to you what they find.
As far as deciding how much value the contributors are providing to the community, I would be perfectly fine with your subjective opinion.
I don't know what types of content producers / projects you are thinking of, so this may not be the type you are interested, but I would offer one nomination of @artist1989. I think he is posting a lot of great content and hasn't got much of a following yet.
Thanks again for doing this project!