Cute idea, but given current technologies, the return on the cycling and braking to get any kind decent range is just not there.
Best case scenario is you would get 10% return.. So figure, you would have to pedal for 100 miles to get 10 miles of no pedaling range.
Not really practical.
It's just like having an iPad.... Great in theory, but other technologies (iPhone) already do the same thing but with greater efficiency and smaller size. "Look at me I spent $650 on an iPad, that really is just an iPhone that I can't make phone calls with, but it looks cool" kinda thing.
I'm guessing the main use is for travel logging with an added benefit of getting some energy back.