Can they make BD/DVD hybrid discs?

[ranma]

HD DVD has it well. Although it won't be important after a few years. But it will certain helps customers to transfer from DVD to Blu-ray.

Typical Scenarios:
1. Kids go to grandma's house and want to watch movies Cars there. Unfortunately, grandma doesn't have blu-ray player or playstation 3.

2. Kids want to watch movies on the road in my state-of-arts SUV. Boom, only a DVD player installed on my SUV.

Even if technically, no possibility for BD/DVD hybrid discs, studios could make another ways around, i.e. bundle a DVD disc in blu-ray package for a small cost.
In fact, I believe, if sony bundles UMD disc in their DVD movies, it will help selling both their PSP and movies in same time.