Here is all the options they have for the RS6:
http://www.ebay.com/sch/m.html?_odkw...Text=&_sacat=0
Just found this little site that supports the front/rear of the RS5.... I might just go this route as it includes Rotors, 6 piston calipers, pads... ect... I selected 6 piston with 356mm rotors (to keep using 18" stockers if needed)
$1812 Shipped?!? Black caliper with silver hubs might get it close enough to the OEM look.
http://ceikaperformance.com/AUDI_RS5...334-p1364.html
Edit, forgot about this company... they were decent back in my BMW days... Link to M5board about them, owner post on there and all.
http://www.m5board.com/vbulletin/e39...ake-kit-2.html
I'm going to shoot them an email and see if they can simply do RS6 brackets with the 3mm added in, although i'm not sure it would matter with that caliper set-up.
Ebay link with ll the options...
http://www.ebay.com/itm/151544117837...%3AMEBIDX%3AIT
Then just throw these on the black calipers...
http://www.ebay.com/itm/351326231103...%3AMEBIDX%3AIT