Frame Rate Interpolation

I would, if possible, love to know a method for improving the overall frame rate of a flash movie using interpolation. I'm not talking about videos delivered through a flash player such as YouTube or Vimeo, but rather vector animations that were common before the days of mainstream internet video. Each flash video consists of manually defined shapes and key frames. These key frames are used to determine inbetweening, or interpolation, motion effects. Since movements, shape transformations, etc are all based on keyframes (scrolling backgrounds and zooms for example) it should be possible to "tween" the master frame rate to 60fps or higher correct? There is a whole host of good stuff from years past (Weebls-stuff, Ebolaworld, Homestar Runner, Newgrounds, etc.) and many of those use low frame rates (one series uses only 12fps) due to performance limitations of yesterday's machines.

What are your thoughts, and has anyone considered attempting to improve old Flash movies in this way?