I too think that an AVCHD compromise of just the movie is a good idea. You can keep the bonus features exclusive to the Blu, much like how the extra bonus official disc will be in the full saga set and the DVD9 was the only one with bonus features for ANHR.

I'm thinking:

Blu-ray disc with movie/menu/special features
AVCHD with movie only
DVD9 with movie/menu only
DVD5 with movie/menu only

And maybe an SD version of the special features on a separate DVD5? I like the idea of having it available in all sizes for easier access. Thankfully the film itself will be the same cut in each version, as people still don't know that the XVID of ANHR isn't 100% finished, but since it is the smallest file size, more people have watched it.