Sometimes setting ideas come at a time when you're not prepared to use them. Other times the ideas are compelling, but the actual gameability of the setting is questionable. It's a shame to waste that stuff though, so I'm going to blog it for posterity.
It's "A Canticle for Leibowitz" mixed with Vincent Ward's Alien 3, with a dash of Dune, and a sprinkling of WH40k.
The central conceit is FTL travel powered by starship drives that are fueled by consecrated communion wafers, a.k.a. the flesh of God. They fly around, still taking many years to complete their journeys, run like little flying monastaries. There are wooden planets, pykrete space stations, prison hulks, peasant farmers, and space-libraries. There are religious conflicts over the use of the communion. There are atheists dealing with incontrivertable proof of the existance of god - or of some kind of thing. There are the ruins of alien civilisations, vast and incomprehensible.
The issues are things like: "What if there is objective morality, and it goes against everything you believe?" "What if there was proof of the existance of a deity, but it wasn't what people expected?" "What if progress isn't always good?"
I think you could play this with Sorcerer (you'd have to add some stuff about Demons and humanity), or hacked Dogs, or a Solar System thing, maybe, if you were less intested in some of the themes, and more interested in the colour.