There is currently a port of Quicklisp (client code) to MKCL in progress on github. You could start using it if you are somewhat adventurous.
First, clean-up your ~/quicklisp directory (ie: rm -rf ~/quicklisp, or mv ~/quicklisp ~/quicklisp.keep, or ...).
Then clone the two small github repositories by doing:
git clone git://github.com/jcbeaudoin/quicklisp-bootstrap.git ~/quicklisp git clone git://github.com/jcbeaudoin/quicklisp-client.git~/quicklisp/quicklisp
Now you can start your mkcl and do this to load the quicklisp client:
(load "~/quicklisp/setup.lisp")
On first attempt it may take a while to get a prompt back since quicklisp/setup.lisp will do a compilation of the whole quicklisp client code. It's much faster later on.
Since you're getting this from mkcl-devel you should consider this code as experimental alpha quality at best.
Enjoy, and bug reports are most welcome.
Jean-Claude