1a. If you feel inclined to read Neptune's Brood, I've got one big regret: I wrote it circa 2010-11, before BitCoin really took off in the public eye, and used the term "bitcoin" for a not-like-our-BtC-honest cryptocurrency. (If I'd known BtC was going to take off that way the year the book came out, I'd have come up with a different name.)
2. Paul Krugman is a cool person to go drinking with in a pub :)
I enjoyed the book a lot, and I was only a bit irked by the slightly-off Bitcoin references and the countersigning etc.
I have a few pages written on the same idea of many disparate colonies but with the twist that quantum entanglement allows for limited FTL communications, which makes an interstellar blockchain feasible.
I'm looking forward to your next book.