First off, the following albums were released a while ago and are still unavailable in Brazil:
Black Label Society - Catacombs of the Black VaticanCrowbar - Symmetry In BlackThere is also a Brazilian metal band called Gloria, which is being mixed with a international singer under the same name.
Also, a Brazilian rock singer called Rodolfo, which recorded the albums Estreito and Rodox, is being mixed with another singer under the name of Rodolfo as well.Also, it would be nice to have the album To The Pain by Nonpoint available in Brazil as well.
Releases are licenced country by country so you need to get in touch with the labels to find out when they will be available in Brazil. There's some more information in this post.
As regards the mixed up artists - please post the details here and it will get fixed.