Jr,

Doubtful you'll ever be 150 miles from a major metropolitan location. Contrary to popular misbelief, run flat tires can be patched.

Personally, I usually end up buying a new tire and use only patched tires in as a temporary solution. But, if you were in a small town, you have several choices.

A) Drive to a larger metropolitan area on the runflat tire. I know people who have gotten 150 to 200 miles with no issues, as long as your speed is kept in check.
B) Have the tire patched and then replace it, or use the patch for the life of the tire as many have.
C) Call BMW Assist via the SOS button and explain you're unable to find a tire for your car, and they'll assist.

Lastly, some of the best service I've ever received has been from small town garages, when when I've been in cars that have suffered meltdowns or ill timed failures. Keep in mind that small town service does not equate to unethical service.

Relax and enjoy your new ride or order the spare, if it's really bothering you.