I have released TruePreview 1.4.  This version includes PPC support (thanks to the persistence of sjk) and adds clicking to the "immediately mark messages as read when scrolling the preview pane" option.  So, clicking or scrolling the message preview will mark the message as read (handy for messages that are too short to scroll).  Note that the click must be in the message body, not the headers.

Thanks again to all of you who have made a donation to support the development of TruePreview!