Startup time is something of a red herring for me, kind of like "give me a single EXE or your language is useless" used to be in the Common Lisp world. I don't encounter this problem in practical use. But then, I don't use Clojure to write scripts that I then run hundreds of times from the shell (but why would you want to do that, rather than write a program that does what is needed to hundreds of files at once?).

Racket is a good one to reach for :)

There are a few fast startup JVMs out there that will run Clojure code.