I love this bike !!! What a brilliantly simple idea! (It shifts from 3 wheeler to 2 wheeler as the child gains speed).
Now if only it was for sale and I had kids of this age again 
You can read a bit more about what makes it unique over at GearCrave.
I saw this in the Poplar Science mag. in 2005 when it was supposed to be available within a year and for $100. I am still waiting.
I wish they would build it – it looks cooool