Sorry, I don't think the tech is there. Either the range would suffer (due to more compact frame allowing for fewer cells safely) or the power would be gimped (to allow for lower overall battery capacity).
Electric cars are competing with the entire petroleum-fuel supply chain, and as such, are fighting a david vs. goliath battle.
That Tesla does this, has won consistently, and wins with style is why their stock is up 500% over the past year.
Of course, they've picked their battles, and fighting the S4 or 3 series isn't one of those they're ready to fight (yet). Maybe, like Apple, they never will (Apple ceded the enthusiast/gaming desktop market years ago).
