What started out as a homemade wagon project quickly turned into an actual production car for BMW.
BMW engineer Max Reisbock simply wanted to go on a family vacation but was lacking much-needed cargo space in his sedan; his daughter's tricycle wouldn't fit. He could have just bought a van of some sort and called it a day but Reisbock had another idea. He went out and bought a wrecked 3 Series sedan and took it straight to his friend's garage and got started. It took six months of custom fabrication work but the final result impressed himself and his friends.
After using it some, he showed the new wagon to his BMW colleagues as well as company executives and they liked what they saw. And only three years later, the first 3 Series Touring (aka wagon) went on sale, with few changes made from his homemade prototype to the final production version.