I presented the idea but it didn't get approval. But if I may, why is that preferable? I mean doesn't it take longer to scroll a couple of screens down than to click the mouse once? I thought putting the link atop every post made it quite convenient to reach, no matter where you were in the thread.

I'm not sure I understand what you mean by:
All you need is a basic chaser script which hides the ad instead of dragging it down.
You mean have the scroll be the event which triggers the script instead of onclick?