It most certainly is. Believe it or not, some of the best chefs in New York City are doing so. I am sure some chefs around the world are as well, however, I can only speak for what I have seen.
The first time I had even heard of a steak being deep fried was when I had the pleasure of attending a demonstration of David Arnold’s. Here is a short clip that gives a better idea of who this gentleman is and how his mind operates.
David Arnold is semi-well known in the food industry. He has a very unique style and the personality of what one would imagine an engineer, chef, and scientist hybrid. He is infatuated with cooking proteins sous vide style. Cooking a steak sous vide is great to get it to temperature, but it will not caramelize the outside of the steak, as everyone knows, is essential. The solution – cook the steak low and slow using the sous vide method to the desired temperature. Get your frying oil to a very high temperature and drop the steak in very briefly. By doing so, we are maintaining the beautifully cooked center of the steak while also evenly browning it. Wylie Dufresne and Dan Barber are also fans of this method.
Here is a great reference for cooking a steak sous vide: