It'd be an interesting perk, all right. And probably one that in all likelihood we'll get. Double arrows are a pretty common fantasy trope.
But, as far as actual dual-wielding goes, I wouldn't mind having two crossbows at once. Wildly unrealistic, but just oh-so-cool.
Honestly, the only thing unrealistic about dual wielding crossbows is resetting with only one hand. I'm sure they could cook up some Dwemer magical mechanical engineering contraption that would make crossbows semiautomatic allowing for dual wield, but will they? Not sure. Besides, even if we find a way to make it realistic, I'm not sure if it would be practical..