+1, would love to see examples
I've looked into MovableInk (moveableink.com) for this, but I'd like to know how it affects deliverability.
I don't think video is yet supported. It will take off when all email clients will embrace html5. Here's an article from Feb that mentions it in the wish list: https://litmus.com/blog/email-preferred-more-clicks-conversions-roi
I'd put this in the 'nice to have for custom campaigns'.
Outlook is a long way from adopting HTML5. It seems to me to be a lot of work for little return. In the mean time, it might be worth looking at animated GIFs that will be available to a larger poriton of your audience.
However, here is an example that Litmus put together: https://litmus.com/blog/how-to-code-html5-video-background-in-email