Is there a way to set up KDE4 Konqueror so that middle click opens a file like in KDE3? In KDE3 Konqueror, middle clicking on a particular file would have the same effect as double clicking on it.

My Konqueror behaves like this. You may find Konqueror > Settings > Configure Konqueror > Web Browsing to be relevant. Make sure "Middle click opens URL in selection" is ticked.

Thanks, but I already did that. I did figure out a way to sort of have the desired behaviour.