Seal rows, which are basically just a row with your chest supported on a flat bench are by far my favourite back exercise with dumbbells. I see no one doing them but they are extremely effective.
There is no way you can cheat and let momentum do the work. You can really focus on squeezing your lats at the top of the movement and get a full stretch at the bottom of the movement.
This is one interesting exercise. There is only one thing that troubles me - find a bench high enough to perform this exercise - I am 6'3, and my arms are quite long as well, so I will reach the floor from basically any position. But the idea behing this exercise is pretty good.