I am using Mac OS X, and I have the SQ, KQ, PQ and Larry collections.
And I managed to extract all the .cab files

. For this, I packaged unshield for Fink
http://www.finkproject.org/. So, if you happen to be using Fink anyway, you could install unshield that way. There is also an unshield package for MacPorts
http://www.macports.org/.
Somebody also wrote up some instructions on how to extract the files on OS X:
http://www.dribin.org/dave/blog/archive ... 6/kq_os_x/.