Only white I would say is rare or more desirable than the other colours. And only ever seen one white Z4MR in this country. Few Z4MCs around though, maybe 8-10 in total? Anyone got the numbers?
For those interested I have a link to detailed specification for all Z4M's produced for North America. The link below will take you to an Open Office ods file and you would need Open Office to view. The file is very detailed and contains VIN numbers and all options. (Large File)