Contact cajon makers directly to find cajons made made in Uruguay. Unfortunately most big online retailers and many music stores only carry imported brands. Buying a locally made cajon cyles your income back through your local economy. Below is the link to the active Uruaguay cajon builder:
Listed above are links to the cajon drum builders in Uruguay as retrieved by Internet searches in November 2019. I am sure there are others not listed. Please send me updates and correction if you have additional information. Thanks.