I would not consider this a “simple” mod on a 5th Gen. If you’ve taken your back hatch apart before you’ll know what’s involved in fishing a wire harness through the hatch door, through the rubber hatch boots, into the headliner and down into the rear brake/reverse light access panel. Not super difficult but it will take you a good amount of time and determination. (As in installing the Ultimate Camping mod). And you’ll have to drill thorough the hatch and then seal it. Set aside a long day or two to do it.
It would probably be a good idea for some member to act as a guinea pig and get a light assembly, set it in the proper position, temporarily connect it to +12 volts at night, and see if it’s worth the effort to install it. Take photos and write up a review in this thread. Maybe XD could send a complementary one out for review. Then we all can decide on a group buy.
Edit:
Some suggestions for XD: The wire length of 1.5 meters is not enough for the 5th gen 4R. You’ll need at least 2 meters for all the routing and strain relief that needs to be done. Plus the twin lead wiring is rather fragile for this. It would be better to include a two conductor plastic coated cable that would withstand all the abrasion, bending, and tugging that will be done when fishing it through the 4R hatch and rear pillar innards.
The order might be stuck in the old system, as we have recently updated our website + Backend software to an all-new platform, it's brought on some troubles here and there so this may be due to why you didn't receive that bulb. 
