I think most are oriented toward the automotive aftermarket.
12volt dropping resistor inside or 120 dropping resistor.
Surgery to the switch could be performed. I have some, I look and see what the prognosis is
I make one comment about LEDs. The red/orange LED takes about 2 volts to conduct enough current to shine. The blue and white ones take about 3 volts. The remaining volts that need to be dropped at the ma current running through them is done with a resistor. It is different for red vs blue and different for different battery voltages. Instead of just using these to look cool (oh I like the green LED, with a purple body) The resistor LED voltage could be utilized as part of a safety monitor. Stacked battery mods could have an LED wired for each battery and resistor adjusted to just light if voltage is adequate (under load). A power on LED and master switch is sometimes a false safety indicator if one battery is dangerously low. And a forgotten power switch (left on) could drain
batteries. The next vape could be the LAST. Unloaded voltage monitoring isn't enough. Underload monitoring, each cell, would be a big safety feature. Food for thought, I don't do high volts myself.
Rocket