Hello,
Just letting this list know that the cffi-newtypes branch at http://common-lisp.net/~loliveira/darcs/cffi-newtypes/ includes, in addition to the new type system, a forward port of James' cffi-encodings branch.
In addition to CLISP and SBCL support already provided by the cffi-encodings patches, cffi-newtypes includes support for OpenMCL, Lispworks and Allegro.
The original discussion can be found here:
Subject: a thought on string encodings http://thread.gmane.org/gmane.lisp.cffi.devel/292