The beast you seek is called a linear link. It is a chainsaw blade that attaches to a skil saw wormdrive or a Bosch wormdrive. You can find it on the web at
http://www.linearlink.com/testimonials.htm It is in my opinion the best tool second to the chainsaw itself. It will easily cut a 12"x 12" like it is a 2" x 4". Good Luck.
