You know, I absolutely love the Pugsley for its ugliness and presumed practicality in the conditions it was designed for... but the thought of having to waste all that energy pushing those huge tyres on a touring bike is too daunting to even warrant the brain power. I have enough trouble pushing 1.75" tyres on my current utility MTB riding to and from work.
Central Australia is not a place to be toyed with. It's seriously dangerous country because of the heat, the aridness and the remoteness as much as anything else. If your adventurous desires get the better of you, do some research first, especially on how to manage water supplies.