I don't know anything about the STAR*DRIVE setting, but I think that any setting where there are a number of human (and/or near-human) races occupying space that was once the domain of some long-gone "seeder" race has possibilities. Consider what can be done with the SM2 setting.
* The Sianetic Harbingers are gone. They're presumed to be extinct in the time of The Imperium of Man, but they managed to transplant humans from Earth to other locations in the galaxy thousands of years previously. Why they went and did something like that is a mystery. So too are the questions of where they are now, or where they died (or even if they died) and when.
* Humanoids aplenty! There's humans, neo-humans, humanoids, transhumans and the like - and that's just in The Imperium. Add to that lot races like the Idorians (distantly related to Terran humans) from the other side of the border, as well as the growing numbers of telepaths within the Imperium, then stir and simmer gently.
* Adding just one more element of spice to the mix, the Metamorphs from 'Aliens and Artefacts' (page 42). Their origins and just as shrouded in secrecy as their purpose. They're long lived (if not immortal) and they can look just like us! (Yipes!)
Smoosh these elements together and you get the following:
* The Sianetic Harbingers are not dead, but they're not well either and require an infusion of younger blood in order to survive. Their days of Glory and Dominion are but memories in the minds of silent dreamers as the last, tired vestiges of a once great civilisation sleep the eons away far from prying eyes. Their future and the promise of renewal beckons but for now their legacy and their inheritance lies in the hands of their greatest of servants.
* The Metamorphs range throughout the races of Humanities, singularly and in small groups, intent on fulfilling the mission programmed into them by their long-sleeping masters. Century after century they labour and toil to alter the genetic destiny of Mankind until they have created suitable "mates" to complement the genes of the Harbingers and so breed their Sianetic Inheritors. Sometimes their methods are subtle, and at other times they're brutally direct, and at all times they gently pull the strings of humanity in order to bring about the birth of a new Race of Man. This sort of thing takes a real measure of power to manage, so how far does their secret influence go?
* Mankind(s), for the most part, remains oblivious to the hidden truth in their midst while the various "stepping stones" along the Metamorph's path (the transhumans, neo-humans and so on) all jockey for prominence. What happens to them when the Inheritors come forth to find a bunch of scruffy-looking "lower downs" kicking around those parts of the Galaxy that they might consider theirs? Will the Inheritors bathe the galaxy in light or drown it in darkness?
There you go, nice broad strokes to begin with. Who wants to go next?
