This was mentioned in the press last autumn but I think casually dismissed as a pipe dream, but Warner have invented the 'Total HD' disc, designed for playback on both formats and to be showcased at CES..... Oh my. The mind boggles what the cost and yields might be like for such a thing.

http://news.com.com/New+disc+may+sway+DVD+wars/2100-1041_3-6147053.html

In other pre-CES news, LG have confirmed they will have a dual format player at the show.