There are supposedly 100s of forthcoming commentaries in various series by various authors, but the accuracy of this somewhat dubious. Authors often commit to projects they cannot complete due to a variety of circumstances.
An example is the Word Biblical Commentary on 1 Corinthians. It has an ISBN number (084990238X), but there are conflicting reports as to who is actually writing it and when:
So, various sites list at least four different authors,and even the publisher doesn't seem to be sure. A close personal correspondent of Dr. Clarke says that he is in fact working on it and is surprised that Thomas Nelson and Linda Belleville still have outdated information. For now, I have both Clarke and Belville listed to cover the bases, but hopefully there will be some clarity down the line.