It looks like Mercedes-Benz is planning to announce a C-class convertible/cabriolet. We already have an E-class Cabriolet and the S-Class, but now it looks like Mercedes is going to complete the lineup by introducing the C-Class Cabriolet as well.
The prototype shown above, looks pretty close to completion to be honest. The car above has a hardtop but the production car will have a soft-fabric roof mechanism.
Mercedes offers a sedan, wagon, coupe and well now this. Sounds pretty good to me.