electric supercar, why do you tease us so? Mercedes is latest to throw up a prototype of what it expects future rubber burners to look like, and its SLS E-Cell doesn't disappoint. Based on its petrol-guzzling SLS AMG model, this beast produces 526 horsepower and 649 pound-feet of torque, thanks to four motors (one for each wheel) allied to a battery array that can provide an industry-leading 480kW of juice. How fast does that get you to the magical 60mph marker? Try four seconds. There's a handsome 10-inch infotainment panel in the center console, which you may see after the break, but the best news is that this prototype can be driven now and could well turn into a production Benz at some point in 2013.