For rally cars, a popular swap is the syncro rear-end, tranny and suspension from a passat, and then for the front suspension you can swap in various other big brother VW suspensions. None of them are direct bolt-ins, but completely doable.
But as an actual expedition rig, it would be sort of useless. Tiny trunk, tiny backseat, is there even a hitch available for them? The only good part would be the TDI engine that would get you over 40mpg with a good range. But I doubt the syncro tranny could be mated to the TDI engine, so you'd probably be stuck with the gas options. It would sort of be a 'just because' build. Not really any logic to it.