Sadly, this was the plan for the DVD releases all along.

The Grindhouse is broken
It looks like there will be no DVD release for Grindhouse in the immediate future.
Death Proof and Planet Terror are getting seperate releases this fall.
Death Proof will come as a 2 DVD set with 30 additional minutes of footage, four featurettes a Double Dare trailer and an art gallery. Likewise Planet Terror will come on 2 discs with deleted scenes, featurettes and trailers.
Both titles will be available seperately for $29.95.
Death Proof arrives on September 18th and Planet Terror follows on October 16th. Let’s hope the full versions of Grindhouse is on the way as well.