Test fit all the parts together.  I'm using metal elbows in the corners to pull them together and add strength.   We need to test the assembly and make sure the LED panel would slide into the box and not bind.  Also wanted to make sure everything worked the way I expected.  I did run into one minor issue.  I have metal elbow braces for each of the corners.  When the LED panel is in place I can not access the the elbows for the last end piece because they are under the LED panel.  This was easily worked around by putting the 9in filler backing piece on that end instead of  in the middle.  This allows access to the elbows from the back with the LED panel fully in place.

The back provides all the strength.  Note I had to move the 9in piece in the middle to the end to be able to access and secure the elbows.

Nice tight corners, pretty happy with that :D

Complete box.  The LED panel is not installed.  I assembled this first then tested inserting the LED panels

First LED panel installed, you can see the open end.  For the final the LED panels will be one piece (gluing them together), and will have the LEDs installed.

All assembled.  The box is pretty heavy.  I am going to have to adjust how I plan on hanging the box to account for the extra weight.

Cutting out the slot for the power and USB plug

Looking very nice !

Odd and Ends    

Printing out the LED brackets/holders.  Each will hold down 7 LED strips.  I printed out 66 of these.

On the small proto type, I tried out the quick connectors.  These where major fail.  Half the time they did not make good connections and when they did I had significant power loss, I am going to solder all the connections.  I am planning on providing power at both ends of the LED panel.  My concern is that this might not be enough, I might have to also provide power in the middle.  Note in the picture above the only wire I had available at the time was Red cover, please understand that the one on the Ground side did go to Ground (I picked up some black wire).