This would be a humongous undertaking. In fact, a better idea would do one for one of the big subreddits.

The N/S on reddit is much higher than HN thus your task would be much harder.

I really like the idea of HNM, the need for quality editorial guidance in the age of information overload is something that has been discussed many times, starting with Alvin Toeffler.

It does exist:

The Redditor:

http://www.reddit.com/r/theredditor

I think they're digital only at the moment, though.

The only way to know for sure is to actually do it. Go for it.