+1 -- I like this idea too, similar to Twitter feeds... ajax style loading of more if you'd like to see more right in the page.... ultimately there are a few options I'd love to see... one is better pagination, and the other was released as a hack by Appsmagnet called Latest Comments First -- they have some great modules too. A combination of Latest Comments First and "more comments" would probably fit with your idea.
Check out the Latest Comments first feature -- this might make the experience better if you would find the reverse order helpful. Ideally, I'd like to be able to toggle that per user and right from within the comment thread.
http://www.appsmagnet.com/activecollab-main/achacks/latest-comments-first/
And I love the idea of "more comments" the way twitter does it. I will see if we can include that in Latest Comments First hack. I also note your wish to toggle the display on the page. Will consider that.
For anyone looking to do away with back and forth / reloading pages for comment viewing, checkout our latest module - Inline Pagination. It's a nifty little productivity enhancer you will fall in love with! Our clients did ;-)
So I love leaving huge comment trails but I hate having to move between pages like we currently have to.. Kills the conversation.
Would it be possible to have comments loaded in, if you needed to see more perhaps clicking "load more comments" would be neat!