Had we been wild and spontaneous enough to buy a MacBook Air in Australia in 2011, we'd have been looking at a 15 percent premium over the US price. According to MacRumors, throwing some Adobe software into our antipodean shopping cart would have pushed that disparity even higher -- to as much as to 75 percent. Which is why the Australian parliament has been investigating the way tech giants price their goods in that country, and why it has now formally summoned Apple, Microsoft and Ad