This post describes generally how to create ajax paging comments, how to package the created comments into a feature, and how to override default views created by modules.

Ajax Comment Pagination

You know the biggest problem with comments? That's right, getting them to page using ajax so that users watching videos don't have to reload the page. Good answer!

So how does one go about making this happen in Drupal 6? Very easily actually. One simply makes their comments load in a view, and uses Views built in ajax to handle the pagination.