I started a project to port Emacs (the C parts) manually to Clojure, with the Emacs Lisp automatically transpiled into Clojure in 2012, most of the work was done in early 2013: https://github.com/hraberg/deuce

It can boot Emacs on the JVM and take simple commands, but not much more. It's my intention to eventually revisit this project, but not sure when.