Well good news. I have successfully installed the OEM camera on a 2013 SV without the requisite wiring in the kickpanel. My issues of not finding +6V were due to the reverse light fuse being blown (likely from the DRL module that was added for Canadian import laws). Doing this my way requires wiring the camera directly to the AV unit. The various posts on here really helped. All I needed to buy was the camera, handle, and some 4 conductor wire.
A few things to take away:
1. Instead of removing the rear left C-pillar trim, I just loosened it off at the top and used some of those wire pulling tools for installing home theatre systems etc... I had the camera in and the wired up to the driver kick panel in less than an hour this way. Toughest part was fishing the wire through the rubber boot connecting the c-pillar to the lift gate.
2. The wiring behind the AV unit took some time to figure out, but its straight forward now. Interestingly, the negative (black) lead on the camera doesn't need to be hooked up. Not sure where it grounds (either the mounting bracket or the image shield I guess, but I left it floating.
3. Because I wired the camera directly (no harness), you need to supply your own pins. You only need 4, so I cut off the camera connector leaving enough room to strip and solder both sides of the wire.
4. Wiring for the camera is as follows
Red (+6V) -> Pin #39
Yellow (Video) -> Pin #40
White (Shield) -> Pin #60
I used the 4th pin from the camera to use the camera sense (Pin # 58) and wired it to a screw on the AV unit (chassis ground).