It's not out. I just PM'd Jean Sexton on Facebook, she's the editor for ADB. She let me know the book is still awaiting some artwork (deckplans, mainly) and is currently on hold until the art gets turned-in and approved.
I for one would love to see this - not only do I love Trek and Traveller, but I was working on D6 Prime Directive for ADB, turned in 5 chapters, and then it kinda went quiet from there as other projects like this one took precedence... So if PD:D6 has to be canned so something else can come out, I'd really like to see that something else come out...