Women in finance. Seriously, it should be a good topic for any research since we do have lots of research in economics, sociology and psychology about gender difference and sentiment difference. If you agree with Shiller that sentiment is an important factor of behavioral finance then gender should be the next thing to explore. We do have gender topics on corp governance which are published in JoF and JFE, so why not this topic? Remember, top journals want readership and citations, and this should attract a lot of readers.
Football and finance has been published on JFQA so we are now very much near to a period where seem-to-be-irrational things catch the eyes of top editors. In crazy time, we need crazy things.
A couple of years ago, not many thought islamic finance will attract a lot of attention. Now, we have gender finance, sport finance, anything else? I would go for online betting finance.