Looks like to build electric car is not that difficult, nor that expensive. This car along with about 3 more was built in University of Transport in Sofia, Bulgaria -
http://vtu.bg/ .
For this particular car, they used some Renault as a base, kept existing manual transmission and removed the air conditioner. The battery used in this car are "normal" lead batteries, one under the hood, and four more in the back.
The car is equipped with solar panels on the roof which are used mainly to charge the 12V car battery, but theoretically may help charging the main batteries.
Due to high price the car does not have super capacitor, nor "bust" function.
The engine without the batteries costs between 1000 and 2000 EUR.
This particular car can "travel" 100 km.
Another interesting thing is that even the transmission is manual, you usually do not change the shifts, but almost always use 3th shift. 4th shift is used on highway, and lower shifts only if road is really bad.
In additional of this car, they built some with automatic transmission and lithium-ion batteries.
Side view:
Side view:
Back side where batteries may be seen.
Under the hood - small engine, big battery