DISCLAIMER: Since high voltage electricity is involved in this project, this needs to be mentioned. I do not condone working with high voltage electrical devices without assistance of a licensed electrician. I do not take responsibility for any harm or damages caused by using this deign.
Now the fun stuff.
My personal opinion is that having any sort of disbursed lighting behind the TV or a PC monitor is easier on the eyes when watch the screen. I have installed LED light-strips behind my TV but LED light strips can be expensive especially if you want to include them I your home automation. This solution for backlighting your iMac is much less expensive and utilises the hole in the iMac stand.
- E27 Smart Lightbulb (I used a LIFX WiFi bulb)
- E27 lightbulb fitting with a cord and a switch
- 3D Printer + Filament
iMac backlight bulb holder front 
iMac backlight bulb holder read 
The 3D design is simple. The pictured lightbulb fitting fits snugly inside the 3D printed part. The flange goes on the outside of the iMac stand, and the screw is on the inside. The lightbulb fitting and cable runs through the centre.
On an iMac, the iMac power cable typically runs through the stand hole. I removed mine and ran it on the side so that the hole is clear.
When the iMac is placed against the wall, the light from the bulb will disburse off the wall and give you a nice soft backlight.
3D Printing
