I could see elephants being massively used in Europe (or elsewhere) for riot control and as draft animals. You can easily use an elephant to move heavy objects and even use them to plough fields.
Source :
http://www.bbc.co.uk/news/uk-england-24745705
His Majesty Royal Elephant RCU (riot control unit) moves to position during the Great Riot of London. The Elephants usely moved without equipment and were "dressed" on the spot with heavy armor. The first use of "Riot Elephants" happened in India, during the Indian Rebellion of 1857, when a British officier decided to charge a mob of rebels with unarmored draft elephants belonging to the Royal Regiment of Artillery.
One of the most famous souvenir of London, the police elephant called Max, symbol of the Constabulary elephants patrols. Max is the hero of one of the most viewed Children's television series in the Commonwealth "Max the justice elephant".
Drawing of Max, his colleague and brother Tim and Skippy the Police Kangaroo :
The use of domesticated "public service" Elephants isn't restrained to the British Commonwealth. The introduction of Elephants from Canada to USA developed a new task for them, the ranch elephants. Those elephants were popularized in the US audience, by the well-known book : The Cowboy and his elephant.
http://www.indiebound.org/book/9780312304065
The other utilizations of domesticated elephants around the world include : forestry, ranger patrols, construction, cattle protection, disaster management, execution (in Saudi Arabia), pet animals, military use and many more ...
I even think it could be a nice way to avoid the extinction of those beautiful, clever and massive animals. We just need to decrease the price of their tusks and to make them profitable as domesticated animals. Perhaps we could even automatically harvest their tusks (under anesthesia) and sell them openly to decrease the price of smuggled ivory. With a small selling price and regular offer, savage elephants wouldn't be killed anymore.