The "State of the Rowland" thing went well. Didn't have a huge audience but one excellent suggestion was made for Forgotten Futures; as of a month or so ago G.K. Chesterton is out of copyright, and there would appear to be no reason why I can't use his work. Some of his fiction is borderline fantasy and SF, and I think that his style would work pretty well. I also know at least one expert on him, Dave Langford.
As a first thought the books I would want to base things on would be:
The Napoleon of Notting Hill
The Club of Queer Trades
The Man who was Thursday
Not the Father Brown stories, I think. Any other suggestions?
I'm running At The Mountains of Flatness at ten - I asked for six players and have nine sign-ups, fortunately I brought loads of character sheets. Just hope my brain is up to that many players.