Neat stuff! I commented on the ActiveState post, but for completeness, I modified your code to support mutual recursions, and used jorend's isTailCall() to make it safe to call an optimized function in a non-tail-call context.
http://the-dubois-papers.blogspot.com/2006/03/python-tail-call-decorator.html -- http://mail.python.org/mailman/listinfo/python-list
