Beware, though --- it's not done yet, so it has some fairly obvious bugs. I'll be working on this right now, but feel free to report bugs anyway.
And if you hate the change, feel free to complain. (I couldn't stop you anyway.... :-))
I'll do a write-up later about how the threading and display works. For now, you can play with it on a long thread, like the site redesign post.