"One self-contained HTML file."

That's a good idea. Would be great if people can use these apps once done.

Also, leading up to the Round, can people submit tasks or ideas that people want to see built? Try to make it as relevant as possible and dialed-in to something people want.

I recently built a single-page RSS reader, but am using a proxy to get through CORS limitations. So it's a 219KB single HTML page, but it also sits alongside a couple of other files on the web server. The HTML file can be loaded from the local filesystem, but that would need CORS Unblock extension to run properly. Just something to think about. As such, the competition could have "pure" and "stacked" variants.

Also, are you able to follow development once the competition ends? Maybe a 10 day development window for anyone willing to continue?

I liked he idea, Would you ever consider separate ratings by model, or is dealing with model choice itself considered part of the skill?