When I approached a custom 4x4 shop in Colorado Springs with my design, which used the pinch weld and the frame, they said, "No way."
They told me that you need more "cushion" between the rock rail and the body, or else the rail could crush the rockers up into the doors. Thus a body mounted rail would not be good. You have to consider that when you "use" your rock rails, you seldom rest gently on them. It's usually more of a 6-12" body-slam drop.
Also, attaching to both the body and frame causes a big problem because of frame flex. I know I get major frame flex in my truck. I've got flex pics where... Well, I'll just show you. Here's a pic.
Here, the bumper is pushing against the trim on the DR side, and there's a 1.5" gap on the other.
I've tried to find Gerald's write up on his steel plate rockers, but I can't. I know I saw them on the forums at some point, but can't find them now.
With no lift, I need something that's "snug". The tube style rails I've seen would ruin my ground clearance.