The weight of a dumbell row should not be as important to a bodybuilder, as is the ROM and the full extension of the exercise with a moderate weight.
A "kroc" row is a powerlifters or strongmans concept. In both sports, momentum is allowed and advocated. It helps. In strongman, a kroc type row, or a cheat row will help you lift atlas stones easier and flip tires. Though I would never advocate a "kroc" row. It's usually just someone with an ego trying to impress someone else. It's about as cool as loading up 20plates on each side of a leg press and moving it 3" x 10 reps and thinking you actually did something worthwhile in your life.
Also I would argue a bodybuilder should NEVER do a kroc or full body row, its simply idiotic. Take your legs completely out of the equation. Your hip flexors and quads should not be doing ANY lifting as part of a "row". Kneel on a flat bench, start with the weight on the ground, and row it up as high as you can into your chest/lat/oblique area depending on the portion of the lat you are attempting to isolate.
Also if you are doing this correctly you will be "shrugging" the weight the first 12-18" off the floor, meaning your arm is straight and it doesn't begin the pulling portion until a certain distance has been traveled. Once your bicep takes over, you have now eliminated any remote chance of successfully pulling the weight to the proper part of the body if you are going too heavy. Show me anyone who can hammer curl a 150lb dumbell for even 3" in a strict motion like a row forces you to do at the top portion of the lift.
Heavy rows have their place, for certain, I do these too..but i would never be so foolish to use any portion of legs in a "row". That is what "LEG" day is for.
Remember, "stupidity is simply a TALENT for misconception".