hi Connectme - seems like the main problem here (if I read you correctly) is that the mobile version of Safari that is found on the iPhone does not support Flash. The YouTube embeddable video player is a Flash app so it also doesn’t work in Safari on the iPhone. In fact, pretty much all embeddable video players (YoutTube, Vimeo etc) are Flash applications and therefore will not work within the browser on the iPhone.
To get around this, the iPhone opens up the Youtube iPhone app in order to play the video in a dedicated frame - trouble is (as you pointed-out,) the Youtube app then replaces Safari on your screen for the duration of the video.
While we realize this is less than optimal from a landing page perspective (it would be great to have the call-to-action etc remain accessible *while* the video is playing,) the issue here is really to do with the restrictions of the mobile version of Safari and not the Unbounce page publisher.
Does this at least address the issue for you? Let me know if I have missed something here…