I think what you're trying to ask for has been talked about in
this thread.
In short: Ain't gonna happen.
In long: The information required to pull something like this off is not sent via the UI. The closest info you can get would most likely be the delay listed in the examine window of any given weapon. Even if a macro/timer
could be constructed to do what you are asking for, I would assume that it would need to be manually modified with each weapon that is equipped.
In my opinion there would be too many factors to take into consideration when calculating the true delay/swing time of a weapon (which I'm sure the game probably does use; why else would they list a delay time in the examine window?), whether it be the weight of the weapon, the strength of the wielder, the user's dexterity/agility, etc.