FTX/OrbX are creating FS11 all by themselves it seems.
Their coverage of Australia (Red, Blue, Gold & Green Region) is easily in the top 5 of all addons ever made for FSX. Importantly the performance is very good which makes it an excellent FSX addon for those on marginal hardware. Try their Tasmania (AU Blue) demo
here (lots of other freeware on this page).
When it comes to the payware FTX Australian airports they seem intent on pushing the technological and resolution boundaries with almost every new release which is great as long as you have the horsepower to run it all properly. Marginal FSX machines beware! The FTX payware airports work fine by themselves but to get the full experience it is advisable to have the underlying OrbX region (mentioned above) installed as well.
To complete the Australian experience there is also have the
freeware OZx 3.0 package and
Ants Aussie Airports.
Then, their photorealistic editions of the Italian Tuscany coast (north of Pisa) + Elba Islands is also well worth getting if you have broadband. It is available
here. While you're there download the Grand Canyon as well.