Powered Play lights are excellent. The guys who run it are also top notch.

I used it to put lights inside my Dreamforge Leviathan crusader (pic in spoiler to not derail the thread)
I put the main part in the chest and then ran a light into the head and one into each of the smokestacks. I need to go back and make actual smake plumes for it as the pic just has wadded up paper towels to show off the light.