You can get comments pushed into the page you are currently reading using this small greasemonkey script:

http://share.shmichael.com/hn_comment_embed.user.js

It shows a small tab on the right side of the page that expands to display the relevant HN page.

Here's a screenshot of the comment panel, once you open it: http://shmichael.com/wp-content/uploads/2009/11/hne.png

And for chrome, ported by a friend:

https://chrome.google.com/extensions/detail/hhedbplnihmkekhg...