BMW has recently unveiled the first “i” sub-brand models, the entry-level, mega city car i3, and the super sporty hybrid i8, but the company is on track to deliver more i-badged vehicles within the next few years.

According to the usual BMW insider Scott27, the Munich-based automaker is toying with the idea of a longer i3 model, as well as a potential convertible variant of the i8. While these are simple extensions of the current offerings, two new models will take these concepts a step further.

Meet BMW i4 and i5. The i4 is said to be based on the i3, a sportier version with 2-seats, think a mini-sporty car with a plug-in electric or range-extended electric drivetrain.

BMW i3 and i8

The “iPeople” in Munich may see the BMW i4 as a more accessible offer for those running short of money when looking at the i8.

On the other hand, BMW i5 is seen as the ultimate test for BMW i, and will be a mid-sized four-door sedan with Coupe-like design cues, again using the powertrain from the BMW i8. The design strategy is still being discussed, but one would expect to see i-specific cues, such as sleek aerodynamics, rear hinged doors and appropriate space for four people.

Both i4 and i5 will also use cutting-edge CFRP technology in their construction.

With the BMW i3 and i3 launching in 2013, the insider says additional models should be expected near the end of this decade.

In the upcoming months and in 2012, BMW will intensify their marketing efforts around the new i sub-brand, offering customers extended insight into the new philosophy and what BMW i stands for.

For now, we’re labeling the i4 and i5 as simple rumors…