Last year I wrote a short post with some ideas on how to generate citation styles. The idea being that whilst there are many styles of referencing in different journals, there is a finite set of elements: plain, bold or italic; all authors or et al. after 3; volume + number or just volume and so on and so on. Computationally, it should be possible to construct a set of questions based on these elements and have a style pop out the other end.
Well, since then I’ve moved to LaTeX and of course, it does precisely this for you. Just “latex makebst”, answer a long series of questions and you’ve got a custom .bst file. More details are available at the LaTeX Bibliography Styles Database.