If you’ll accept a layman’s opinion, the only thing I see there that I would comment on, if I were to critique, is the same-side-double-sidebar layout. I’ve seen it on some sites I’ve visited from time to time, and I’ve often wondered myself whether it challenges most users as much as I think it does me. I’ve been known to stop visiting sites when the value of the content is overshadowed by the difficulty of the layout, though this type of layout is fairly rare in my experience and I don’t think it’s ever been the last straw to make me abandon a site.
I think if the elements in the sidebars relate well to each other horizontally as well as vertically it can be a very good choice—but the other sites where I’ve encountered it don’t strike me as having tried very hard to work that angle. Unfortunately, since as I say I haven’t really encountered all that many sites with that kind of layout, I don’t think I could really say what would make a given site work better.
I hope that isn’t completely useless.