The dual currency story reminded of a research question I thought might be potentially interesting (assuming it's not an old, mined out topic). Way outside my field but it might be worth passing along.
Some friends of mine are serious shellac collectors, the kind of people who spend hundreds of dollars for a hundred year old record. It's a big, well established market with the occasional natural experiment that ought to stand up to some analysis, but what caught my eye was the fact that though mainly cash-based, there's a significant barter aspect. what's more, the cash barter mix has been in place for a long time and seems relatively stable.
Seems like there ought to be some fun questions you could ask about a market like that.
Paul Krugman: Japan the Model
1 hour ago