The Dawn of Darkness News page has word that plans for this commercial Quake II conversion have been scrapped. Here's part of the update, which goes on to describe plans for the free release of some of what they've worked out for the project, as well as plans to continue to develop Dawn of Darkness as a franchise:

It is with a great sense of bitter-sweet that we make the announcement first mentioned last month. Bluntly and plainly:

Dawn of Darkness, as a Quake II total conversion, has been officially and voluntarily cancelled.

Realizing that there is no market left for commercial Quake II products, that the Quake II engine is showing its age, and with a desire to do justice to the Dawn of Darkness concept, we have ended development of the conversion. Though it pains us to cancel the project, there are several good things about it...