Building some small upper cabinets that will go above a couple of undercounter wine refers.
The cabinets will have LED lights on the bottom and inside at the top.
Here is the SU concept.

The pictures will show how I am going to rout out for the wire. 
I'm going to double up the bottom shelf and cut matching grooves into the bottom and tops of each piece.  The light will fit into the recessed hole and the wire will run out the back and through the wall to plug into the transformers.
The series of pictures should explain what I'm doing.

This shows the inside of both shelves.

This is where the wire will exit from the back, into the wall.

This is with the shelves put together.

This shows the wire going through.  Once plugged in the LED light will push up into the hole.