I think not.
Hell, when I first heard that Reese Witherspoon was going to play June Carter Cash, I almost broke a plate. Similar reactions will probably be generated by the rumors that this actress:
I'd say Kidman's extraordinary height is an obvious issue (as one commentator on this NY Magazine post points out), but maybe she can pull it off. In the end, Witherspoon proved me wrong, so it'd be a nice surprise if this one managed to work out as well.