You might want to consider running something like the Raspberry Pi Zero. Looks like the Nano is 45mm x 18mm and the Pi Zero is 65mm x 30mm. If you could fit the Pi Zero it would probably make your life a lot easier.
This is a great suggestion; the Zero has enough oomph to run the JVM, which gives you access to Clojure!
I had the most luck installing the Zulu Embedded version of Java, and I've had a Clojure webapp running on my Pi Zero for over a week now without any hiccups.
