BMW says more PHEV derivatives are in the cards as they migrate technology from the i sub brand to core models.
However I'm not sure if the 4 counts as a core model, but logically what the 3 gets the 4 should as well...The German automaker has announced that it will unveil a BMW 3 Series plug-in hybrid prototype along with a new generation of hybrid vehicle concepts sporting technology currently used in BMW i models. In the long term, BMW is planning to offer plug-in hybrid versions of all its core-brand models. The 3 Series plug-in hybrid prototype will feature a four-cylinder gasoline engine mated to an electric motor that is based on the BMW eDrive technology currently used in the i3 and i8 models.