This is a follow up to this question: Creating Vector Polygons with rendering performance like GISCloud?
In his answer, Yagi outlines a rationale for encoding geographic information in an image format and decoding it in the browser. He observes that "Currently, to do this, you have to roll your own". He also observes that there's currently no standard for this.
Given the awesome performance being demonstrated, it seems like the community might benefit from a standard. From my understanding of the problem, it sounds like a standard way of dealing with it could be implemented. Call it B-WFS.
My question, then: what would a useful protocol for encoding vector data as images look like? Is there something making it too complex to tackle usefully, or is it just a case of "no one's done this yet"?