Apparently you can do it yourself now: http://navigation.teleatlas.com/bmwusa

The cost is $245 and from the description they will send a USB drive with the maps, the page also asks for your VIN. This would presumably be used to create the FSC code.

__________________
Current:
2013 BMW 535i GT- Neptune Blue-Venetian Beige Nevada Leather-Fineline Matte Wood Trim-ZCW/ZVP/2ST/3AG/416/677
2005 BMW X5 30i- Kalahari Beige-Sand Beige Nevada Leather-Dark Burl Walnut Trim-ZCW/ZPP/ZRC/508/522/609

Former BMW's:
2010 BMW X5 xDrive 48i
2003 BMW 745Li
2001 BMW X5 30i
1995 BMW 525i