If you are not in imediate need, you can get a complete front brake kit from ebay for $120.00 and $7.00 shipping that has these Mercedes part numbers 001 420 99 20 (Pagid pads), 126 421 05 12 (2 Zimmermann rotors), 140 540 12 17 (4 brake wear sensors) and 001 989 10 51 (2 Mercedes brake paste). The pads are OEM from Pagid, meaning they are the exact same pads you would buy at your Mercedes dealer. While there are no available OEM brake rotors on the market, Zimmermann is the finest German rotor available, Porsche guys swear buy them, here is link for an example:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1847729561