If I were going down this route, and Im saying this not because Im a reformed Dubber or anything but I would go with the Touareg. Solid powerplants, great all weather abilities, actually very good offroad, seals that keep everything out, good fording depths, good in the mud (like anything, dependent upon tires), and actually designed to be off road capable (unlike the Porsche twin). I would get my hands on one without the air suspension (or swap it out with adjustable coil overs or the stock steel springs) and start working on fabbing everything else up.
You can get a full belly skid system and a winch mount for behind the front bumper. 95% of the stuff posted on this site can be done by a smart driver in a TReg.
Oh, and dont forget the painters mask (something only a Dubber would laugh at).