Swain has been working for the last few years on a guidebook to Southern New Hampshire climbing. He has posted about it on the various climbing boards from time to time. He uses the name Gunkswest on the boards. I have no inside info but my guess is that he has no plans to update the Gunks Guide. I could be wrong but it is a big job and I think he has moved on.
Here is his user page on mountainproj:http://mountainproject.com/u/gunkswest//106642247