Was something like this used on the pre-2010 episodes of The Simpsons for the fxx version? Granted, they also cropped and stretched them, but they definitely used some sort of super-duper upscaling algorithm to make new transfers out of the existing ones in lieu of an actual fresh hd scan of the original elements.
Speaking of the prequels, Bill Hunt theorized in his review of the bd set that something like this might come along to do a deep analysis "guess and render" for a new 4k version. It's already been almost four years since then.