I just took over maintenance of Locale-Codes, and released 3.00 today to
get it up-to-date with respect to changes made to the standards over the
past few years.
I am happy to add additional code sets, provided I have a reliable
official (or semi-official) source of the data. Although I love
wikipedia, I don't consider it official (or semi-official). I did a
quick search and didn't find anything... but I could easily have
overlooked it.
If you can provide me with a URL where I can get the data (for free),
I'll be willing to add support for the 3166-3 codes. Unfortunately, the
ISOs typically aren't available for free (which drives me crazy!).