I cannot answer for Mongoose, of course, but Samardan Press is working on a third-party campaign setting that should come out in the early summer. At least, that's my goal.
Flynn's Guide to Azri Drakara will provide a basic sourcebook for the Azri Drakara sector, a region in space approximately a thousand lightyears rimward of humanity's birthworld. A frontier sector of the human-dominated Dracosian Republic, this region is home to the Azri Drakara, or the Worlds of the Drakar, a warrior-like reptilian race that is quickly expanding its territory after gaining Jump drive technology several centuries ago. Eight other, smaller polities call the region home, as do four new alien species.
This sourcebook will provide details on each polity with worlds within the Azri Drakara sector, a collection of interstellar corporations, details on each of the alien species likely to be encountered in this region of space, the worlds of the sector, the history of the region, several ships commonly encountered in the region, and a small bestiary of creatures encountered of note. In addition, this sourcebook will contain notes on adventure opportunities and mysteries within the sector, and will provide sixteen patron scenarios as well as a full-length adventure designed to introduce players to the Azri Drakara sector.
As I said, that's my goal, and I think it's easily accomplished with a little more time and some elbow grease.
I imagine that this book will weigh in somewhere between 80 and 128 pages, and should be available in both PDF and POD, depending on your preferences. Prices have not yet been set, since I don't know the final number of pages until I get it all done and put together, but I'd imagine the PDF will range around $6-$8 US, and the POD will range around $12-$16 US. Again, this product will be available in the Summer of 2008.
With Regards,
Flynn