Cargo-area power port wiring harness/supply available on 2007 Equinox LS?

[Razzmatazz]

I'd like to add an accessory power port (cigarette lighter) to the cargo area of my 2007 Equinox LS. Such a port was available on the 2007 LT2/3. There is an empty 20A fuse socket (#40) for "Rear Accy Pwr Outlet" under my hood (which I'd be happy to populate with a 20A fuse). I can easily (drill and) add an aftermarket flush-mount cigarette lighter port to the trunk compartment. But does anyone know if there is an untapped wiring harness (or wires) under the cargo area that I could tap for an aftermarket power outlet? The only harness that I've found is for the trailer-harness in the jack compartment. I'd be willing to remove the cargo flooring in order to access wiring for a power outlet if I knew for certain that it was there, but not just for an exploratory mission to see if it's there.