I think creating something new, then marketing it, will cost Warner much more than simply adopting existing proven technology that essential does the same thing.
Doesn't hybrid SACD covers all bases? You have a hi-res stereo and multi-channel layer which is copy-protected. You could put an "Enhanced CD" layer as the CD layer, which can include some video and computer multi-media content (such as what's available on the Ray Charles "Genius Loves Company"...