The best thermal control override I’ve seen is on the Nitecore Concept 1.

The Concept 1 is an expensive 1x18650 tube-shaped sideswitch light. Due to its lack of heatsink fins it heats up fast and and can rampdown fast. However, you can override the thermal rampdown at any time simply by holding the sideswitch down. While the button is held down, the light stays at maximum turbo. When you release it the thermal stepdown is reset and it will rampdown rapidly if hot.