I wanted to make the LEGO #4551 Crocodile engine in green with working lights, but the 1x6 brick for lights will never be released, so I made one.  My power drill had a 3/16" drill bit, which is a tiny bit smaller than a lego stud.  On step 04, I use the drill to make the hole a bit bigger.

The drill bit fits through two technic bricks to give accurate holes.  The frame is moved by stud jumper offsets so that 9 holes can be placed in the back of the brick.  The holes in step 08 are cleaned up with a Dremel(tm) until the lights fit.  There are two ways to adapt 9v lights to the box.  The destructive version is step 9, where the drill is used to make room in the light holders for the bulb.  The non-destructive way is step 10, drilling a 1x2 trans-clear brick to make a light box like the old 4.5v box.