I just whipped up a heat map based on the Australian State boundaries using the instructions in Brian Munz's custom regions extension. This was actually quite simple. I created the necessary polygon shapes using the tool on the web at http://gmapspolytool.gmapify.fr/ which is mentioned in the instructions in Brian's original post at http://community.qlik.com/thread/4089 So for anyone needing custom regions or state based regions for their specific geography, I suggest you give it a try. For those who need the Australian state boundaries, I have done the work for you here. Just use the attached version of the extension object, and have a look at the attached QVW that utilises it.
ALSO within the QVW (on a separate sheet) is an example of using a fixed JPEG as the basis for the mapping. This alternative approach does not require a link to the internet in order to fetch a Google maps image. However the downside of this approach is that it does not have the polygonal outlines of the states, just the usual bubble shapes plotted on top of the map. You can take a look at both in the file and choose whichever option you prefer.