If this sort of thing fascinates you as it does me, you might be interested in the latest Charles Stross book that features relatavistic finance as a major plot point. Here's a preview chapter: http://www.tor.com/stories/2013/06/neptunes-brood-excerpt
Mr. Krugman himself thinks it's "the best thing by far written on the subject to date" (http://krugman.blogs.nytimes.com/2013/05/20/the-theory-of-in...)