Good luck on your search! The internet is going to be your friend on this.
site:craigslist.org X5 4.6is - Google Search
The above link should give you all of the hits for a X5 4.6is that are on Craigslist.
As I have said to other members of this forum that if they find a car in my area I am more than happy to go check it out for them, take pictures and if they arrange all of the service inspection stuff I will take the car and drop it off for them.
I am sure you might be able to find other members who will do that for you!