Um, Jonathan59, how exactly do you base a unibody SUV (or SAV to quote BMW) off of a unibody car? It would require a total change of the frame which would mean that it's not "based" on the 5-series. I think you mean the engines are shared between the X5 and the E39. Besides, the X5's are built in Spartanburg (I actually got to see them being built) and the E39's are, to my knowlege, still built in Germany. Also, the X5 is AWD and the E39 isn't. That would mean some pretty major driveline changes.
By the way, I drive a Land Rover Discovery II, but you can count me as part of the small population that actually uses it as intended. So far, it's been used on icy/snowy, unplowed roads, up mountain trails, down mountain trails, across I-75 in Florida countless times, carried my BMW 633 over 1,000 miles on a trailer (that's around 5,000 pounds altogether), carried my girlfriend's worldly possessions across the aforementioned I-75, and been driven mercilessly in Land Rover's get-togethers. Don't make generalizations about SUV's and their owners (although sometimes it is actually true). My Disco does corner very well for an SUV because when off-roading, a low center of gravity can save you just as much as when you're cornering hard. You don't want to roll over on the side of a hill, do you? But, you've also got to know how far not to push it. It's like trying to go 200+ mph in a sports car. Not a good idea unless you're on the salt flats. But, people do it anyway. Hey, at least Darwin's theory is proving to be true. Sorry for the long post, but I just couldn't keep quiet