Fortunately our truck has (as an option) a trailer tow package. This includes, along with other goodies, wider power mirrors. These are just the ticket for this application. On my other trucks I've tried 3 or 4 different add on mirrors, the best non viberating ones were the add on kind that mount to the front fenders, attaching in under the hood and clasping onto the tops of the fender wells. Not to appealing visually but works great.
For trailering with our hot rod, the Mckesh door mounted clamp ons seem to work best with minimal viberation.