Karl,
Thank you for a truly remarkable video! Your space-time stretcher fits wonderfully with the theme of this contest, "Show Me The Physics!"... better yet, "Show Me The MODERN Physics", which is, after all, what FQXi is all about! You are right when you say that the usual rubber sheet analogy is a bit of a let down, as it already requires gravity (to generate a downhill force) to explain gravity... The space-time stretcher is so much better... I want one! :)
Your video is well produced and very pedagogical, and it is, in my opinion, one of the very best that has been submitted to this contest. I hope it makes the finals and is recognized by the jury!
Congratulations!
Marc
P.S. If you have a chance to view, comment and vote on my trilogy of videos entitled "This Is Physics" --- where I try to convey the "fun of physics" by focusing on some of the greatest moments of its history --- it would be quite appreciated!