Man, that is a complete buzz-kill.

It's your decision, but I would by-pass the dealer and take it up on a major level with BMW Corporate. Do NOT take delivery of the truck. Tell them you paid for a mint $93K truck and explain to them what has occurred. If you do not mind the wait, tell them the dealer can use this one as a floor model, and that you demand a different X5M. Also, if you have any attorney friends ask him/her to type it up on legal letterhead. Can't hurt to try and swap out.