On Sep 22, 2013, at 11:24 AM, Faré <fahree@gmail.com> wrote:
(defmacro assocf (item alist &optional default &rest keys &key test test-not key)
 …
… side-effects ...

Lispwork's has cdr-assoc, which works on places:  http://www.lispworks.com/documentation/lw50/LWRM/html/lwref-618.htm

See also https://code.google.com/p/cdr-assoc/  which I wrote some years ago, and I have no memory of what it's short comings might be.