In my games, the RT's dinasty held the knowledge of a second warp gate leading to the Tau Empire region, a place not known even by Tau and Kroot.
This was an awesome source of cold trade and even the PC's Dinasty came from a Sector "over-there'. With time, they started getting ultimatums from the Tau they dealt with that the Dinasty should turn to the Greater Good or else the Tau would denounce it to their enemies.
They stalled and moved all their assets to Calixis and eventually killed all their ex-ally Tau that were making such threats. In Imperial Registries, the Dinasty moved through the Jericho-Maw gate.
However, at some point the "Dinasty gate" was engulfed by a warp storm in real space, which destroyed a large portion of their fleet and left a single heir and a single ship who was being educated in Calixis. However, that RT has contracted a Nurgle dicease that is killing him slowly and so I am planning on giving the Dinasty its old leader back, in the form of a new RT pc.
With that, I am considering re-opening the warp gate at some point, and so I need to populate it with a Sector or an Expanse. It needs to have both Imperial and Tau presence and be basically a war zone today.
Do you have any sector in fluff you can recommend me to read about?
So I can build a map for future endeavors.
As a last case scenario, I will just make do with the Jericho reach.