After reading all that...

Follow-up question: Is it possible via hacking/homebrew software to instead render something at 1920x1080 and send *that* down the wire to the TV at 1080p (assuming the Wii U video settings are set to 1080p obviously)? Or if we try to do that, will it be forcibly downscaled to 1280x720 before being re-upscaled to 1920x1080, thus looking just as bad as before?

Answer: I don't know. I haven't been able to conclusively test that yet. But I'm in the process of working on it. Getting stuff working is easier said than done.