Cool, think I'm gonna solder an LED into mine and see if it works, the little pictogram on the button IS translucent.
The power window switches already have LED's in them but Ford-in it's infininte cheap-a** wisdom, simply didn't bother to wire them up. There's threads on here with how-to's.
As far as the trunk button, I assume it would be the same type of LED as in the stereo or headlight switch, BUT there are only 2 wires going to the button. I never traced them but I'm guessing it's a simple switch that just closes part of the circuit, triggering the release. The Central Timing Module disables the switch once you hit a certains speed, maybe that's what the other wire is for? Guess we'll find out...