In the United States, there are (as of this writing) 39 malls mentioned on their Web site,
www.shoppingtown.com. Almost half of those are in
California, and five are in the
St. Louis,
Missouri area. The remainder are scattered about the
east coast and the
Pacific Northwest of the States.
Thanks to Augusta for convincing me to continue my research: Yes, the Sydney Shoppingtowns are related. The American ones are owned by Westfield America, which is a division of The Westfield Group, which is based in Australia. (Again, all information gleaned from their Web site, and a bit of digging around.)