Frank Tipler argues for the existence of a multiverse by expounding on the argument for local only - limited to light speed interactions - and the conclusion is then that Everett's multiverse is the only possible candidate for the true interpretation of quantum mechanics.
http://lanl.arxiv.org/abs/1008.2764
http://lanl.arxiv.org/abs/1008.2764
I show that observations of quantum nonlocality can be interpreted as purely local phenomena, provided one assumes that the cosmos is a multiverse. Conversely, the observation of quantum nonlocality can be interpreted as observation evidence for a multiverse cosmology, just as observation of the setting of the Sun can be interpreted as evidence for the Earth's rotation.