It's true that the file sizes aren't different by a factor of two (the keyframes are probably not as many for 60p), and it should be managable. But I don't know of any site that provides it, then again I have never looked for it.
What you can certainly try is creating your own homepage in HTML5 end just embedding the video. That should work, but your webspace provider would have to provide enough bandwidth. It should be possible though.