That's too far from the bike concept and way too expensive.

I may try electrifying my bike, a local guy does this and it looks reasonable. You can see the pictures here:

http://prodavalnik.com/sglobyavam-elektricheski-velosipedi-p...

For the electro-motor, inverter, controls and batteries you pay:

1. 250W motor 36V+ lead-acid battery (3 х 12V 9Ah)- 300 €

2. 250W motor 36V+ lead-acid battery (3 х 12V 14Ah)- 323 €

3. 250W motor 36V+ li-ion battery (36V 10Ah)- 524 €

4. 250W motor 36V+ lithium iron phosphate battery (36V 12Ah)- 633 €

4. 250W motor 36V+ lithium iron phosphate battery (36V 15Ah)- 790 €

5. 500W motor 36V+ lead-acid battery (3 бр.х 12V 9Ah)- 338 €

6. 500W motor 36V+ lead-acid battery (3 бр.х 12V 14Ah)-363 €

7. 500W motor 36V+ lithium iron phosphate battery (36V 12Ah)- 674 €

8. 500W motor 36V+ lithium iron phosphate battery (36V 15Ah)- 830 €

9. 800W motor 48V+ lithium iron phosphate battery (48V 15Ah)- 980 €

10. 1000W motor 48V+ lithium iron phosphate battery (48V 15Ah)- 1025 €

Range is 30-80 km and you can always pedal more. I think this product could be a hit, with a bit better design and manufactured at scale.