I had a friend in high school make a swamp cooler type system with a regular cooler that a person might take on a picnic. 12V fan and pump. It worked fairly well in our dry climate. I have not seen anything like it on the market.
Back in the 1980's a company by the name of Red Dot made air conditioner units you mounted on top of the cab. Just googled the name seem to still be in business. Had them for after market cabs on tractors, combine, construction equipment, and trucks.