Fast startup time can be achieved through Drip[1], which is rather easy to setup for Leiningen use.
Might want to give that a try too: https://github.com/josteink/lein-drip
https://github.com/flatland/drip/wiki/Clojure/_compare/87336...
I tried it with the new leinrc command, and got the same result (in both cases I verified that drip servers were being started using `ps aux | gerp drip`, and they were).
I've filed an issue here: https://github.com/flatland/drip/issues/50