Originally Posted by Varroa
I saw a thread by somebody who just took a round cooler and found a pot with the same diameter and slit the pot inside the round cooler. He then drilled holes in the pot which lined up with the valve hole in the cooler and put in a weldless fitting. Sound similar to your idea.
Here is that thread: http://www.homebrewtalk.com/f11/my-new-mash-tun-268370/
I'm working on one of those myself.