I think the G-wagen is the kind of truck that would be the 6th or 7th addition to my fleet after I won the lottery. It's something that many of us admire and desire, but at the same time we understand that it's an even bigger PITA to own and maintain than a Rover. Not necessarily because it requires as much/more maintenance, but because there are probably no Marty Powells/PT Schrams/Will Tillerys/Paul Grants dishing out cheap and plentiful parts and advice.
There is a guy in Seattle (at the UtiliKilt company, of all places) who drives a diesel G-wagen. Pretty sweet.
If the version of the DC100 that makes it to the US market is any good, it will probably be adopted by the Discoweb Cheapskates in the same way that early LR3s are starting to show up on the trails. Not many people will drop $50k or whatever on a new truck to take it on trails, but once they hit $15-$20k on the used market they'll see some dirt.
As long as amateur mechanics can work on them at home there's a chance they'll be embraced and experimented with. But if they are as electronically complex as the RR mk IV (L450?), forget it. Good old Kennith gets fired up about wanting to remove the entire ABS system from his Disco. Imagine what he'll say about the underwater sonar on the DC100...