Martin,
I saw your post and thought I would respond. I work for Lenox Softworks and we developed a teleprompter application called Script-Q that I am certain will meet your needs. We have 3 different versions of the software, Basic, Advanced and Professional and offer both Macintosh and Windows versions. Please feel free to try the 15 day fully functioning demo of our Professional version that is available at script-q.com and feel free to contact me directly if you have any questions at 413-637-0099.