This vehicle is in the early testing stages but likely no more than two years off. It will likely be available by 2015 either as a 2015 model or a 2016 model year car. The driveline options will mimic the rest of the C-Class lineup but the real question is whether an AMG variant will be available. The current E-Coupe and cabriolet do not offer an AMG model so if one wants drop top AMG fun one has to go for the SL.
What's interesting to note is what appears to be carbon fiber weave for the folding hardtop roof or a combo of metal and carbon fiber for it. This may solve the problems with the weight a folding hardtop adds. It looks like Mercedes-Benz is trying hard to save weight and going topless may not come with the weight penalty it usually does.