I like the +[Gen 1:1]+. Traditionally, Bible verses may be cited in a different way than other works, so it seems sensible to have a unique citation style as an AsciiDoc extension.
We can also include the translation abbreviation, e.g. +[Gen 1:1 KJV]+ or [Gen 1:1 RSV]+.
We'd want to publish a table of supported abbreviations for book and translation names.