Thanks everyone for all their advice and help. To help close the loop on this issue in case any one else out there has the same issue, I could not find an inexpensive LED solution that would definitely fit within the cutouts of the Rampage rear bumper. I found one that was 2mm too large that would require sanding the circumfrence to make it fit (maybe) and then coming up with some way to mount it inside the light can. Not a good solution in the end. The light can cutouts on the Rampage rear bumper have an inside dimension of 102mm (~4.015"), and I have attached a detailed photo from Rampage containing all the dimensions. In the end, my solution was to pickup a set of Rampage driving lights, which are designed and made to fit the cutout, and pick up a lower wattage (35watt) H3 bulb to put in them so they are more in line with appropriate brightness to serve as solid backup lights. While it solved the issue for proper brightness, it did not give me the easy wiring solution of tapping direclty into the reverse light circuit for power that LEDs would have provided me and that was my goal with this idea/thread. Instead, I'll use a relay triggered off the reverse light circuit and run the 12v+ hot line directly from the battery. I figure what time I gain in the ease of installing the lights themselves (versus having to custom rig LED lights even if I could find a set that I could make fit with sanding, bulding a custom bracket to hold them, etc) will even out with the time for running the additional wiring from the battery.