Peppermint Grove, a suburb of Perth in Western Australia, has all the trappings you¡¯d expect of one of the wealthiest postal codes in the country: sprawling riverside mansions, exclusive schools and a yacht club.

But lately there¡¯s a new sign that the Perth elite are starting to tip over the line separating the merely rich from the fabulously so. Glance in a real estate agent¡¯s window, and you¡¯ll often see properties advertised with a telltale phrase: ¡°Perfect for a family office.¡±

Financial hubs such as Dubai, London, New York and Singapore have long dominated the rarefied world of family offices ¡ª outfits that typically cater to a single $100 million-plus client with services that can include managing money, taxes, charitable donations and even household help.