Here's a well used original. Perhaps the first 'base reflex' cajon. Made by Machudo Cajon in northern California in the mid-1980s. Now-a-days there are a lot of cheap bass port cajons available
Cajon Flamenco › Instruments › La Sonanta - Flamenco
Carlos del Castillo's "deDios' model cajon, made by Machudo Cajons. - YouTube
Cajon | Popular Percussion Instruments | DRUM! Magazine
BEAT'ABOX | Singapore Singapore
Carlos del Castillo's "deDios' model cajon, made by Machudo Cajons. - YouTube