Not a bad idea! I was thinking more along the lines of the sides of the hips rather than the back, but still.
I have the D3O armor in my Badlands Pro jacket. I am not real impressed with the coverage of the elbows in the jacket or the knees in the Badlands pants. They are great for direct impacts to the outside of the joints, like the point of the elbow or the knee cap, but they aren't so good at covering the sides of the joints. When you go down, you don't always land on the points of the elbows or your knee caps. It is actually more common to land on the sides of your knees and inside/outside of the elbow. I would like to see the armor wrap around the joints better. I don't know if the armor shape is made specific for the brands or if the brands make their gear around the armor shape?