The motorcycle world embraces a far more diverse range of engine layouts than the automotive world does. A bike's packaging is more flexible, and its demands for cooling and heat management are lax compared to even a basic car. Just how wild you can get in the two-wheeled kingdom? Take a look at this JRL Cycles Lucky 7 and its radial powerplant.
Read the full article on Hagerty.com: https://www.hagerty.com/media/motorcycles/this-radial-chopper-is-patently-absurd-and-its-awesome/
I understand and appreciate the thrill of accepting and overcoming an engineering challenge - for decades my thing has been building motorcycles for riders with disabilities - but I'm not sure there will ever be a useful application for the ingenuity deployed here.
But I could be wrong. If folks are willing to spend stupid money for these things, I guess that's a 'useful appliaction' for the builder!