7 - 1969 Willam City
This vehicle was designed right from a scooter. It’s the product of the Italian Lambretta Scooter Company. The body of the Willam City is made of fiberglass and could hide two engines, either a 125cc or a 175cc unit. Its very square shape didn't help sales and just from looking at it you can tell its design made it prone to rollovers.
However, because the engine is mounted on the single front wheel, the vehicle is incredibly maneuverable.
8 - 1965 Peel Trident
The Peel Engineering company is the originator of the aforementioned Peel P50, the smallest production car in history. Peel was also behind the creation of the smallest two-seater, the Trident. In fact, the Trident is an evolution of the P50. It was designed to be able to accommodate two mid-size adults.
The Trident used the same 50-cc engine as the P50. Getting on board is child's play; all you have to do is tilt the glass roof. However, in hot weather, the cabin apparently turns into a veritable oven.
Fun fact: if two 165-lb adults get on board, they double the weight of the vehicle. The size of the fuel tank is suitably tiny, at 2.5 gallons.