Updating this thread because I finally got a working setup. I waited all summer, trying to keep an eye out for a used Access cover to pop up locally. That was a no-go, so I finally pulled the trigger on an Access Literider from Truck Alterations.
I landed on the Access line of rollup covers because from what I could see, the mounting rails all should work with my bed rack. I just would need to drill new mounting holes in the Access mounting rails to align with my bed rack's mounting holes. My bed rack mounts to the bed through three holes on each side, leading to the utility track. I'm using T-slot nuts in the utility tracks to keep everything bolted down.
So, I got a new Access Literider and went at it today. It took a little longer than I expected, I battled with it all day, but with some persistence, a little muscling and creativity, i got it on. And, I have to say, it seems to fit perfectly, once on.
As expected, I measured and drilled out 3 new holes in the Access mounting rails, matching up to the mounting holes in my bedrack. Once I got those mounted, I test fit the cover. The big unknown for me going into this is if the way i'm mounting the Access rails, which causes them to be a little narrower in width than if mounting the rails normally. I wasn't sure exactly how much narrower this would be and what the tolerance of the cover would be on this. Anyways, once I test fit things, I did see a problem in width. The very front aluminum support bar, which mounts at the front (closest to the cab) was about 1/4-1/2" wider than the width of the mounted rails! I looked closer at the aluminum support and saw that there was an end cap screwed into each end. I removed those, making the total width of the aluminum support rod about 1/4" less, but it still didn't quite fit. The support rod needs to sit in the angled channel that stand up from the mounting rails So, this is where a little muscle came in, using a vice grip and some spare aluminum sheet, i was able to grasp on the angled channel area up front on the driver side and bend it slightly out, just enough to let the support rod slip in. Once that went in, the rest was cake. I did have to slightly bend out the angled channel at the tailgate end, to again let the end support rod sit in the channel. That wasn't as bad as the front one. The other support rods, in between the front and back ones, all were narrow enough to snugly sit in the channel without any muscling.
All in all, very glad I did this and very happy with how it came out.