Cheap option for a fret lights or flashing fret light markers. IKEA make a battery operated set of XMas lights I ripped off a fretboard and placed the lights into fret markers. the battery compartment is small enough to store in Control cavity. This works like a charm and cost me about 3 bux (AUS). Im currently working on a flame concept in a fretboard that will light up the flames red by modifying the same XMAS light package....Mind you if your not at all comfortable with messing with fretboards etc etc . Get a pro to do it..
if you have a junk guitar lying around have a practise...