YouTube playlist of cajons made in Brazil:
Note that not all manufacturers have current YouTube videos. The list on this page includes websites and Facebook pages which may contain videos not on YouTube. The list on this page is current and actively maintained, the YouTube playlist is infrequently updated.

One photo per Brazilian cajon manufacturer in Pinterest:

Listed above are links to the cajon drum builders in Brazil as retrieved by Internet searches in March 2018. I am sure there are many others not listed. Please send me updates and correction if you have additional information. Thanks.