Like tye points out from his googling, the spoken languages are problematic for the two main varieties of Portuguese, but not the written ones. Spanish has relatively minor pronunciation and vocabulary differences in the major varieties---a situation which is much more like that of North American and English English. The major differences there have less to do with one form or another not existing in the other variety, but rather with how frequently certain vocabulary and grammar is used.

I would still argue for more specific encoding internally because it is always easier to go from more specific to less specific, but the reverse is much more difficult. Who knows? Maybe someday someone will want to give Perl Monks lots of money for promoting, say, Perl learning in Brazilian Portuguese, but government regulations prevent them from accepting documentation in Continental Portuguese---admitedly a bit of a long shot... ;)