the lighting effect which results in drastically different panel lighting depending on the sun position and resulting shadows, in order to get consistent looking screenshots, even as I turn the aircraft.
The sun does that in reality with panels - lit surfaces show full daylight (25.000 lux), shaded surface show only indirect light (100-500 lux). So I'd argue that the environment system should really not do what you ask (and in fact, you can't simply flick a switch and make it happen).
Elements that can potentially appear too dark often are back-lit in reality, and the more advanced aircraft in the repository allow you to use the corresponding switch - if instrument back-lighting is done well, it'll even add right with the sunlight (though consistent cabin lighting is hard - I've done it for the Space Shuttle and there's lots of code involved computing the current amount and color of indirect light in the cabin).
As for your request:
If you're a 3d modeler, you could try to reduce ambient and diffuse material channels of the panel objects to zero using blender (or another 3d editor of your choice) and make them all emissively lit - in that way, they'll never change color.
If you know GLSL, you could write a shader which does away with the directional lighting and uses always 1 for the diffuse light factor rather than the NdotL term - and then assign that effect to the surfaces.
Otherwise I don't think there's a viable option.