This light bar holds three Piranha 24 LED boards (MPJA.com p/n 32035). It works well with a pair of brackets designed by @wschadow (https://www.thingiverse.com/thing:2055511).
Install a 5mm micro toggle switch on either side and wire as shown in the photos. Power required is 12 volts 1 amp.
The LED boards are held in place by friction or with double-sided tape if you prefer.
Project cost < USD $20.
I printed this in PETG but ABS or PLA should also work fine.
The author hasn't provided the model origin yet.