I did read your post, actually. To clarify, if you're brushing the brake pad because the rim itself between the spoke-hole edge of it and the tire bead isn't stiff enough, then your positing that the entire rim all the way around is bending through that region such that that bend induced by the contact with the ground at one angle results in flex on the opposite side of the rim in the opposite direction, right? I'm having a hard time seeing that happening. I would think that a non-stiff rim through the central region of the rim between the spoke holes and the tire bead area would behave more like a non-stiff rim in the examples in that linked article, and be less likely to brush the brakes.

So how are you so sure that it's the rim that's at fault for your brushing the brakes against the rim, and not your spokes being unable to keep the whole rim from tilting?