The primary form of libertarian communism that has been implemented is that of the anarchist variety. Even so, anarcho-communism has not been as widely implemented as other forms of anarcho-socialism, yet clearly functioned in some instances. I would cite the Spanish Revolution, the Free Territory of Ukraine, the Paris Commune, and the current establishment of the Zapatista Army of National Liberation as pertinent examples of the implementation of libertarian socialism.
Also, I'd honestly venture to say that you're unfamiliar with some of the "inherent principles" of socialism and communism, given some of your statements in the past.