With Blu-ray DL (50GB) even 1920x1080 is reasonable with MPEG4 depending on how much content we're talking about, although a SL disc of either format wouldn't be enough from the videos I've seen. It depends on the length of the content of the series in question, but 7+ hours of 1920x1080 is definitely possible. If you search around you can find plenty of HD content to judge by.