@webvitaly your plugin works beautifully! Thank you.
I still have trouble, though, with text wrapping around the iframe. The only way I have found to prevent text wrapping around the iframe is to always use the width set at 100%, as is the default in the plugin (by the way just delete the height= parameter and the height will autoadjust to the height of the source, at least for Vimeo iframes).
But if I want the width to be less than 100%, the text always wraps up next to the iframe on the right side. I tried wrapping the iframe in div tags: <div> [iframe] </div>, but that does nothing to prevent the text wrapping.
I tried wrapping it in div + p tags: <div><p> [iframe] </p> </div> but the editor removes the p tags when switching back and forth between HTML and VISUAL.
Anyone know the solution to this?