To GetOffTheX:

~11.5" from the ground to the bottom of the receiver opening on a 2012 X5 Premium with Drawtite, Reese Towpower or Hidden Hitch.

I'll let someone with a factory install give you the height for that hitch. It's the same as the 2011 and that height is posted in one of the forums. If I find it, I'll edit my post.

Update: according to this post 2011 Tow Hitch - Page 5 - Bimmerfest - BMW Forums factory hitch is 16" from ground to the CENTER of the receiver opening.