Better Sun Visor

Whenever I am stuck in traffic while on the way to office on a sunny day, I get irritated that the sun visor of the car is so small that it cannot effectively shield me from the sun. It only gives a small area of shadow region (depending on the angle of sun and position of the visor) and I have to adjust my position to come under this shade! Other cars are also not so different. Can this be made better? Why not a visor which is small in its initial position, but has hidden panels which can be pulled out in different directions to make it bigger (say a panel which is kept rolled inside the visor body normally)? Is this very difficult?