My trunk light was longer than the license plate bulbs. I made what I had worked by jut modifying the metal contact strip in the bulb holder.

Also, if you don't use load resistors (like I didn't) the voltage and current surges from the can system looking for a bulb will kill the LEDs in a heartbeat. I've had 10 completely fail.

I'm currently looking for LEDs with the resistor built in or a more compact load resistor.