Some folks like the McKesh towing mirrors, which are attached to the door by straps with a rachet mechanism. I bought CIPA Universal towing mirrors for my Jeep and found that the curved front surface didn't want to hold the adjustable feet well. I had to use bungie cords to make them stable.
The ones Gerry mentioned are worth a try. Spending more money on towing mirrors is not necessarily a good strategy, at least for the universal varieties.
Towing mirrors are one of the best arguments for buying a pickup truck to tow your trailer! Some of the best towing mirrors are only made for Ford or GM pickups. Good luck, hope you find something satisfactory.