So, in reading a comment from Mick Bradley on the RPGPodcasters mailing list, and his geeking about how cool the Map part of chargen is for Jeff Lower's ashcan, Giants, a thought just dislodged in my brain:
The players and the GM together make the map, right? Okay, so, in a sense the reinforces the Arthurian legend around the King and the connection to the Land. (Unless I'm totally fucking up my remembering of the various Arthur legends, and I'm by no means a scholar on the subject.) So, instead of being a Giant, you're the King of your people. Okay, then you take the element of community in Giants, where your community feeds you, but you need to do things for your community in order to keep it healthy so it can keep feeding you. You twist that to be about taxation and bolstering your people, and you have the beginning of a game about the rules and war-chiefs of ancient tribes (Briton or otherwise).
That'll probably be as far as I'll go with the idea anytime soon, but I thought I would share that with others, in case someone else wants to run with it.