I have been kicking this idea around for awhile, and suppose that it's time to think about whether there is interest in the idea outside my own head.
So, this would be based on the setting from a novel series in which the world population is literally decimated ten years after the "flu" of Year Zero. It's what I would consider a near-future world (I would guess maybe 150 years or so future, tech levels are not dramatically different than today's), with the following presumptions:
- climate change raised water levels, coastlines dramatically different
- very violent storms
- a few years before the events of Year Zero (the year of the first flu), infrastructure changed to put buildings underground
- rail lines on a spokes/hub model
- internet replaced by an ethernet (which allows, at a glance to see if other docks are on/off)
- biobots - 3d printed humans who are created as adults and made for particular purposes
Now, rather than follow the exact plot of the novels, what I'm thinking about is locating the story elsewhere--upstate NY, and rather than Year Ten (when the population has been quite literally decimated--US population estimated at 33 million), put it at Year Four (population would be running about 40% of today's numbers) when existing society has pretty much broken down and this would be the tale of how a community is then built by survivors.
System -- well, I don't know GURPS very well at all, so wouldn't use that, but would be open to having a co-GM who could be the "Rules GM" and handle crunchy bits while I'd handle plot. Free-form is a possibility. I've also considered swiping parts of CoC (strip out the magic and sanity, but leave the stats and skills in). Storyline would be fairly sandbox, although setting and events beyond the community (weather, raiders, etc)
Definitely mature, possibly adult (personally, I find writing sex scenes rather boring, but that's my quirk), since it'd be a fairly gritty survival and, if a biobot was in play, included could be some serious reflection on what it means to be human.