The luxury truck market doesn't seem like something BMW would be interested in. Like another poster pointed out, the X5 was created to take a piece of the SUV-fad market. A BMW X5 truck doesn't seem like it would have much interest at all. If you look at the other luxury pickups out there - Lincoln's Blackwood and the one Cadillac is making (can't remember what it's called), those are both limited production units. Didn't they say they're only making a couple thousand Blackwoods for the year? You have to ask yourself - would the small amount of people who could afford a luxury truck buy one? Most people with the $$$ and want a BMW are looking for sport. I have a hard time equating "sport" with "truck".... although BMW has tried very hard to make their X5 SUV extremely sporty, while being large and AWD.
Personally, I think the concept of a luxury pickup truck is absurd. Trucks are meant for hauling, towing, and other heavy duty activities. I'd be afraid to put anything in the bed for fear of scratching it! Especially during the process of loading and unloading anything into it as well.
Then again, if that picture above is legit, it's just a concept...which doesn't mean squat. Car companies do concepts all the time without ever going to produce them. I briefly checked the internet for more info about the X5 pickup and couldn't find much, other than that same picture posted above. It would be such a waste for BMW to produce it.... I can't imagine that they would actually sell enough to make any money whatsoever. Doesn't seem like good business to me.