Attached is an ebuild script for CLISP 2.28, a popular Common Lisp system for Intel and PowerPC platforms (and others as well). Its home page is at http://clisp.sourceforge.net/ . I think it should go under dev-lisp/clisp. There are no dependencies, except for X (if you have X in your USE variable).
Created attachment 1185 [details] clisp-2.28.ebuild
Neato. Will get to this soon.
Available as dev-lisp/clisp-2.28