Ditto this so many times... so so many times. Sorry to get you potentially excited that someone replied, but i've been looking for replacement visor's (and not just those "clip on" ones) so that it can be extended thereby preventing me from getting blinded on the driver (or passenger) side.
Haven't found anything yet.
I am tempted to take off the visor and check it's hole markings to see if it could be swapped out with another from a different car. I mean, there can only be so man ways to make the mounting points of one of these.