Cole, did you get the diesel? I am intrigued by the dual battery setup.
And I see your point about the Cayenne being near perfect, particularly if you option it right. If my pockets were deeper (and they were once; I bought a new Carrera back in the late 80's and that was my third Porsche) I'd give some thought to ordering one.
Alas, realistically, at this stage in life I doubt if I want to spend that much on an SUV when a BMW or Mercedes is cheaper.
But to answer your question, for my personal use, if I were to luck onto an off road equipped Cayenne the one thing that I can't seem to find in the aftermarket would be proper bull bars, perhaps with a mount for a winch.