HN would fit in as a subreddit on Reddit. In fact, I'd wager that if there was a subreddit /r/hackernews it would look almost exactly the same as this website.
A community that generates a nearly identical content feed seems plausible enough. I doubt the character of the comments would be the same, though. Beyond the obvious fact that HN is a more focused and less populous community, the structure, context, and presentation of the reddits must have effects on the psychology of their users.
Even if you were to replicate the HN content feed exactly on a private subreddit, with the same set of members and the same set of moderators, you'd see a different character to the comments.
There is, and it does (but only because it literally is just a mirror of HN on reddit)