Just bought The Koronus Beastiary and was a bit disappointed it didn't include some guidelines for creating advanced Xenos races, just primitive cultures. Maybe the writers felt there were simply too many possibilities to come up with a proper selection of ideas? Or is there actually a generator somewhere else in the splatbooks (maybe an Ordo Xenos guide for Deathwatch?) I'm missing?
One possibility might be to create the primitive cultures as per the Beastiary and then "advance" them from there... I'm also kind of leaning towards imagining what the original species that "devolved" into the bat-like Species X.101MK2 (or somesuch, don't have the book to hand) on Orn was like, since they had a ship "as big as a War-Sphere".
Or has anyone come up with a guide?