I'd actually been considering hiring someone to run HN, though not to moderate it in quite as hands-on a way as you're suggesting. Interesting idea though.
The later parts of the book (chapter 8 and beyond) seem applicable to the problems HN is facing.
PM me if you want, I'll send you my copy of the book.
On the topic of moderation I would suggest the ability to somewhat "follow" good commenters, and even perhaps block bad submitters. This way, reputation is not only karma, but quality of followers.
Be warned, he's going to strongly advise you to set up a backchannel for public metadiscussion. Jeff Atwood resisted it vehemently at first when another metafilter moderator was a guest on his podcast, but they did eventually set up their meta subsite in the same vein.