TechLighting Track MR16 LED Light.

thingiverse

Track light that sits on a TechLighting low voltage track. You can install an MR16 socket into it, and a couple of bolts (an M6 and something smaller on the bottom) to clamp it to the track and provide your electical connection. The light is aimable via a 30mm ball and socket, and you could add extensions if you wanted a gooseneck. WARNING: DO NOT INSTALL A HALOGEN OR INCANDESCENT IN A PLASTIC LIGHT FIXTURE; THEY WILL BE TOO HOT AND IT WILL MELT. MONITOR YOUR LAMPS TEMPERATURE AND ENSURE YOU'RE NOT CREATING A FIRE OR MELTING HAZARD. EVEN SOME LEDs PRODUCE A LOT OF HEAT. EXPERIMENTAL. USE AT YOUR OWN RISK.