Usually, the more a company reveals on a test mule means the further along development the car is. This B-Class seems to be in almost production guise. The headlight shape looks as though it's finalised, as do the doors and major panel layouts and contours.
Overall though, the next-generation B-Class is very similar to the current model in terms of body layout. It presents a kind of mini MPV design with a short front snout/bonnet and a large rear cargo area with a relatively level roof that extends high right until the tailgate.
This test mule is the hatch variant, a coupe and a convertible are also expected to come out with the new model. It looks like Mercedes-Benz is continuing to develop the hatch version first as there's been no sign of a coupe or convertible test mule yet.
As far as engine specifics go, the new model will be available with a range of small four-cylinder engines, both turbo and non-turbo as well as a turbo-diesel variant. The B-Class is also expected to come out with a hybrid package of some kind which will be in tune with the company's plans to introduce a hybrid version of every model by 2014.
An AMG model is also rumoured to be in the mix sporting a 2.2-litre turbocharged engine producing around 200kW.
The new model is set to be unveiled at this year's Frankfurt Motor Show in September, with production models in showrooms early next year.