Way cool: the most portable of all Common Lisps has received a few modernizations lately. And now McCLIM runs on it too - though of course only on CLX, and thus on OS X only under X11. But at any rate, it's quite an interesting platform. Especially since CLISP is the Common Lisp that most closely resembles a scripting language in terms of its environment.
Hmm. CLISP runs on the Zaurus. The Zaurus also has a system variant with X11. With CLISP+CLX+McCLIM+X11 you should be able to build the smallest reasonably complete Lisp machine in the world on the Zaurus.
At Planet Lisp you can find the original article.