Starting from the move to Mercurial, it's not possible to pull from the repository only the en-US files.
With the help of the bind mount we have successfully made an hg repository with only the needed */locales/en-US/ files and directories. (11 Mo for the en-US files against more than 670 Mo for the whole repositories)
It is accessible from http://hg.frenchmozilla.fr (DNS servers may not be updated yet from your location). The en-US repositories are updated each 30 minutes and if the changes include en-US ones, they are synchronized in our repository (feeds are up-to-date).
