There's probably 3 or 4 vendors on eBay that sell a variety of BMW Motorsports wheels. You should be able to find the black leather wheels with the blue and red lacing, the alcantara covered wheel, etc.

Here's a couple of active auctions:

http://cgi.ebay.com/ebaymotors/BMW-M...35659773QQrdZ1

http://search.stores.ebay.com/RoverA...403503QQsofpZ0

http://motors.search.ebay.com/_W0QQsassZqalbeli

The last seller is located in Sweden, but members here and in some of the other BMW forums reported good transactions and service from this eBay seller.

Hope this helps.