An explanation of all the valid fields can be found at [1]. Copy an existing locale, modify it to suit your needs. Don't forget to escape all characters as Unicode if you want it to support unicode. Compile & install as normal with localedef, add to `/var/lib/locales/supported.d`, run locale-gen, set the various `LC_` variables you want to use in `~/.profile` or `/etc/envionment` or whatever.
