Bibtex Automatic replacement of 4+ authors with et al.

As the comments have mentioned, I would recommend against maintaining a bibliography with the abbreviations done by hand. This is exactly the sort of automatic thing that bibtex should be doing for you. That said, I don't know how to control this sort of thing with bibtex. I seem to remember that natbib did automatically truncate author lists, but I can't remember how much control it gave you. (indeed, this could well have been one of the things that made me move to biblatex...)

The biblatex solution would simply be to set maxnames=4 as a package option. Incidentally, biblatex is no longer in beta: v1.0 was uploaded to CTAN yesterday.

I feel a little guilty answering my own question, but this is for the sake of people looking this up in the future.

Bibliography style files dictate how the bibliography is typeset and which fields are kept/modified. As such you simply have to select the right \bibliographystyle{style} before calling \bibliography{bibfilename}

In my case, I had left over boilerplate code from the template I start from for all my latex articles. Revtex sets the style automatically when specifying the document class (and the journal substyle), however I still had a \bibliographystyle{plain} left over from my template. All I had to do was remove that line in order to let revtex select the bib style automagically.

A quick search for "et~al." in the .bst file will reveal the code where this is done. In my case (apsrev.bst) I found that the code will look for the key word "other" in the author list and replace with "et~al."

This means I just have to modify the bibitem author to replace all the other authors with "and others". It's not really the correct fix, if it requires modifying the bibtex database file. But it helps, if you want to add your own entry where, for certain reasons, you want or have to truncate the author list.