Ok. I'll play.
I haven't heard anything at all but it is cool to think of what the options could be... So, where could you hold a 5,000+ mile off-road rally?
USA/Canada - You'd have to circle around some and double back on yourself a bit to fit that distance in any place with tough terrain, but possible. If you added Mexico you could make it interesting but then security concerns might come into play.
Australia - Maybe some good options but I don't see it ever being held in just one country.
Mongolia/Russia and a 'Stan or two - Interesting?
Back to Africa - Would they do that?
Hmmm. It's fun to spin the globe around and wonder...