stratford_noob I think an extension will be able to do that, but I've not seen it done yet.
I also received requests to implement it, but nothing concrete has been started.
Changing the post order probably isn't too complicated, but the logic for loading prev/next pages will have to change, and the new post composer will have to be moved to the top instead of bottom.
While it probably won't require changing core, you might have to replace the whole DiscussionList PostStream view method with your own logic. Such changes could interfere with other extensions that extend that function's output.
