Proposition 8 is irrelevant. Marriage is a religious sacrament. Religions, protected by State and Federal constitions, remain free to marry whomever they wish.
(As both Federal and State constitutions bar States from endorsing religion, states should stop issuing marriage licenses.)
The collection of legal obligations currently associated with marriage can already incorporated in a Declaration of Civil Union. As Proposition 8 affects only the issuing of marriage licenses by the State, Gays in California remain free to combine a religious marriage with a civil union.