I built something very similar for my truck. I actually saw one in person on a pace Edwards cover like yours and modelled it similar. I have a soft roll up between rails cover. I needed six inches of clearance under my bike rack rails to roll the cover. I welded up two bars of 1-1/2" square tubing to sit on the box rails. At each end they have a piece of square tubing going down into the stake pockets. Then about 1/3 and 2/3 of the way down the side rail I welded a cross rail. The cross rails are 1" square tubing and they go up 6" first then cross the bed. I then bought two rooftop style bike racks and bolted them to the cross rail. I will try and take pics tomorrow and then try and post them.

I may have figured pics put!
I had made my cross rails removable from the lengthwise ones, but never have removed them.