Placing the camera in a nitrogen pressurized housing and installing a decent sunshield works wonders for lowering and stabilizing the temperature for your camera. If you do a quick search, there are a wide variety of housings available.
We discovered the value of sunshield - not only for cameras but all our outdoor electronics while deploying a system in the Horn of Africa. We found aluminum housings to be the best material for passive cooling - but you need to protect the housing from direct sunlight.
That's fine. I stated 120+ and as the highest temperature ever recorded on earth is 56.7 °C (134 °F) I was giving the temperatures we've recorded and performance as a reference for hot ambient outside applications. The key we've found as stated previously is shade and then enclosure ventilation. If equipment is in direct sunlight or does not have proper ventilation you can expect much higher internal temps and the plastics will warp and sunbake.
We have internal applications in manufacturing and refining where temperature get much hotter in the locations cameras are installed as well.
You answered your own question. We have several cameras installed in desert and 120+ degree areas. You can have fans to help pull out heat from the enclosure and possibly utilize some sort of heat sink but the best thing you can do is use a shade and make sure your enclosure has proper ventilation. If you go with active cooling your power budget (and solar array / batteries) will go way up.
Here's the thing we've found out though - with simple heat exhaust and shade cover pretry much any cameras we have installed in high temperature locations perform very well. We have some that have been going for over 4 years with temps reaching 120+ with no active cooling and they are still working no problems.
Bob, good question. Are you looking for fixed cameras or PTZs?
I know, for instance, Axis talks about cameras up to 75C with their 'active cooling' (-c) lines but if I am reading the spec sheet correctly it's like 75W!
Btw, we have one post related: Deploying Cameras in Super Hot Environments