Just to address some points on the potential Spinward States sourcebook.
First, it will not be just a rehash of the Regency Sourcebook. The Regency Sourcebook was about only one thing: the Regency. The Spinward States sourcebook will be about all of the Spinward States. It will also cover all four sectors of the former Domain of Deneb, including the very dynamic piece on the other side of the Rift.
As has been stated before, the Spinward States include the Imperial Regency, the League of Deneb, and the League of Spinward States. Plus the Aslan, Zhodani, Floriani, Regina, and other small states. It is truly a dynamic region.
Yes, there will be some overlap with the Regency Sourcebook, as far as the world data is concerned, because there has to be. But the differences will be far more noticable than the similarities. Granted only 46 years have passed, but a lot changed in those nearly five decades!