Original MB roof bars do fit a c-coupe with a pano roof. The bars sit on the very edge of the roof away for the moving section and also sit on rubber feet (so you won’t damage the glass). If you open the doors you will see the positioning marks and the cut away section on the rear windows is for the rear roof bar.
The W203 roof bars posted in the eBay link above won’t however fit, you need the CL203 version (which are narrower to fit the narrower roof profile). The MB part number for the CL203 version is B6 685 0257. These come up on eBay, however the model number is not on the roof bars but the car type they fit is (ie. W203 or CL203) - ask the seller to confirm.
Thule roof mounted bike carriers can be directly attached to the MB roof bars using the T-Track. Not sure about other makes (MB bike carriers will also fit!).
If buying bars on eBay, make sure they come with the keys to unlock the bar ends and also the long reach allen key – otherwise you cannot attach the bars to the roof.
Currently on eBay:
Mercedes Benz Roof Bars on eBay (end time 10-Apr-11 11:52:04 BST)
Mercedes Benz C Class Basic Carrier Roof Bars B66850257 on eBay (end time 10-Apr-11 21:55:06 BST)