I mentioned SCL a few days ago, but I should have said more since SCL 1.1 was just released.

A new release of Scieneer Common Lisp 1.1 is now available. The website has recently been updated and the evaluation product may now be requested and downloaded from the website.

The Scieneer Common Lisp implementation features support for Symmetrical Multi-Processor (SMP) systems on various Unix based platforms, making it ideal for scalable multi-threaded enterprise and performance computing applications.

Note that evaluation versions are available.