As usual, it is only available as part of a $200+ collection:
http://www.logos.com/product/29051
A few other highly sought after resources were only available this way as prepubs, but soon after the collection was released the individual volume became available. Horton's "The Christian Faith" comes to mind immediately.
So I'll hold out hope that the same happens with this, certainly one of the most excellent commentaries on any portion of scripture. Similarly I'm still waiting for the prepub containing Beale's NT Theology to be released with the hope Beale will be freed from bondage to the collection.