Closer to the mark examples are all over the place with different levels of success. The most prominent are the governance structures of multiculutral and multi religious states of south and southeast Asia, Singapore is a prominent oneone, but India and Bangladesh have also adopted similar models to differing degrees. Basically, where multiple ethicities or religions coexist together, their civil and sometimes even criminal law are the laws of their religions or ethnicities, and only when a dispute is between people of disparate groups does some supreme, secular society wide set of laws apply. There are also examples of this throughout Africa, and truly, this is the way most of the world operated for thousands of years before states had defined borders.
Of course, these aren't truly what we are talking about, they're close, but in my examples there is still an overarching state that is arbiter of last resort, and there is nothing voluntary about the associations, they're usually hereditary and imposed by the state with at most an opt out of tribal/religious law. The concept as noted in the diamond age differs in that associations are voluntary (both on the part of the individual as well as the organization) and prominently, you're subject to the law of those you violate, or, if two members of two different groups are in dispute, the dispute and a resolution are handled diplomatically.