Factory tow mirrors

[Happy Camper]

Do any one out there know of a slide on mirror that would extend the up and down viewing range of the factory tow mirrors? It does not look like it would be too difficult to manufacture to slide down over the sides and sit on top of the factory unit. I tow a 5vr and like to view the tires on the trailer as well as the top to see if overhangs etc will do a number.

Thanks in advance.