D7000 HD video format - can each frame contain metadata?
No. Standard video formats do not work like that and the D7000 is no exception to this.  Conceivably it can be done but I am sure it is not on anyone's priority list. I worked for 9 years on video processing and rendering software and there are more important problems to solve. Indexing and managing that data would also become a problem. When working on functions that process video from a series of still images, it makes it vastly simpler to assume the metadata of the first frame applies to all subsequent ones.

Obviously I understand why it would be desirable but this is the same on all cameras. GPS is another perfect example. On cameras with built-in GPS, only the location of at the time video recording starts is recorded while you may be shooting from a moving vehicle and cover some ground while recording.