For BMW's 100th birthday,the revealing of a plug-in supercar is reportedly planned.

According to Auto Motor und Sport, BMW will reveal its i9 plug-in hybrid in 2016 to celebrate the automaker's 100 years of existence.

Auto Motor und Sport says that it obtained information from insiders.  This info suggests that the i9 will be as follows (via Google Translate):

"The anniversary car is a kind of super-i8, actually deserves the i10 model name, but already Hyundai uses. That's why BMW is the name i9 talking. As a plug-in hybrid sports car is powered by a combination of electric motor and six-cylinder and the system output of 362 hp of the i8 clearly surpass. Also, the electric motor itself will be stronger."

"The BMW i9 sports car gets heavier than the i8 due to the larger motor having 1490 kg curb weight. From zero to 100 km / h, the BMW i9 likely accelerate in less than four seconds..."

The BMW i9 has not been officially confirmed by BMW, but there have been hints of its (or a vehicle akin to it) existence:

BMW Vision Future Luxury Concept Plug-In Hybrid Gets Revealed

Source: Auto Motor und Sport