Mike, are you familiar with the Power Straight? It is a pull then push exercise that does develop the upper back very well. You can see a video here:
https://www.exrx.net/WeightExercises/Power/WtPowerStraight.html
I occasionally have my pole vaulters use that exercise as part of a gymnastics routine. I actually like it quite a bit but I think too difficult to ramp up the intensity for highly trained athletes and still keep it safe.
ELITETRACK Founder