I also think the standard lighting in the cargo area is insufficient, just like how my protege5 was.
In my Protege5, I removed the stock cargo light bulb, bought some LED ribbon strips and wired it up to the contacts of the cargo light. This allowed the LED strips to turn on and off whenever the cargo light does. The strips were adhesive backed, so I stuck them on the left and right underside of the cargo area "walls". Wiring stayed on the inside of the interior panels and under the cargo floor to go to the other side.
I used 6 inches of LED strip on each side. This is pretty much what I used.
http://www.elementalled.com/waterproof-flexible-led-strip-light.html
What's nice is that you can buy as much as you want and cut any length you want, then just solder wires to it accordingly. So if you want more light, then you use longer strips.
I chose waterproof because it was for another project, but they work well on the interior because the LEDS are molded in and protected, where the non waterproof strips have the LEDs exposed and open to possible damage in case they get bumped into.
The difference seemed like day and night and I never had any issues with it in the P5.
Here are pictures of the P5's cargo area. I plan on doing the same with my CX5 since the cargo areas are similarly shaped/designed.
