Here's a vid of an E53 3.0d support vehicle (with serious mods of course) up against a BMW X650 Dakar motor bike on a 4 mile section of the Paris to Dakar race. Worthwhile 7 minutes showing the X53 doing what we would all love to do. Surprised they didn't use a 4.6 or 4.8. Spot the X6 having a go as well. Stay watching till the very end, not sure what happened to the X, overall great footage:
http://www.youtube.com/watch?v=ptxmebNTCDk&feature=PlayList&p=4779CCC0645 5D4C5&playnext=1&playnext_from=PL&index=14
And for those who'd like to see an E70 in thick sand, check this out:
http://www.youtube.com/watch?v=fqvWHu6eAEw
Apologies to those that may have seen these already.