Since each dealer operates independently, BMW NA claims to have no control over what a given dealer does. This is the same excuse NA gives for parts price gouging.
Here's a suggestion, while not optimal, may get you some info.
When I bought my car, I ran a Carfax, and found that the car had been registered in VA. I wrote to the VA DMV and requested the records on the car. From the certificate of registration, I got the original owner's name and address. I wrote him, and he was kind enough to engage in email correspondence with me, and gave me a rough sketch of the service history. Since he bought the car before the BMW NA "free maintenance" foolishness, he maintained it properly from his own pocket - even the drive train was serviced at 1500 miles! He turned out to be a car nut.
This may not work too well after the car passes through several hands, but I was satisfied, having become the second owner at 58k.
Ed in San Jose '97 540i 6 speed aspensilber over aubergine leather. Build date 3/97. Golden Gate Chapter BMW CCA Nr 62319.