It is hard to get good photos of fog. This vendor site does a much better job of that than I could:
Home page - Patio Misting Systems, Mist Fans, Fog Systems: Aero Mist Outdoor Mist Systems, Outdoor Misting Kit
I don't see though how you will find a 1000 psi system that delivers the small amount of fog required for your purposes. These pumps are positive displacement pumps meaning that the amount of water delivered is a function of motor speed. The smallest CAT brand pump that I see delivers 0.5 liter/minute. The pump head does have a pressure relief valve that recirculates outlet water back to the inlet but if you do this with too much recirculation the water heats up beyond what is tolerable for the pump.
World Leader in Triplex High Pressure Pumps
For my system I used a pump that delivers 2 liter/minute at 1800 rpm but then I used a variable speed electric motor that allows me to run the system at 300 rpm or less to get 0.3 liters/minute for my 50 cubic meter room.
But I don't see any commercial systems with that small of a pump and a variable speed drive motor and you probably don't want to undertake building one yourself.
If you don't want an ultrasound system then I would suggest looking at a small swamp cooler.