Californian Company Mobiky USA Selectron offers an innovative folding bike dubbed Mobiky Genius.

The Mobiky Genius can be folded in 2-3 seconds. After folding the Genius can still be rolled along, which is quite convenient.
This compact city bike comes with 3 speed internal gear hub and disk brakes. The height is adjustable to fit most people. Mobiky has supposedly spent 2 years and over $1 million of R&D in developing the Genius.
This is reflected in the price for this design award winning folding bicycle. The MSRP is $999.99. Amazon.com has it also listed for $999.99.
Folded Dimensions are 25" x 12" x 32" and the unfolded Dimensions 50" x 18" x 41" for the Mobiky Genius.

Mobiky is apparently also working on compact electrical powered bikes.
You can find more details on the Mobiky site.