I am looking for an article that I think was in FHB that showed a roof strategy that allowed for a vent channel above a continuos layer of rigid foam.  From what I remember the build up was (from inside to out) 2x framing > 1″ rigid foam attached to the top of the 2x framing (no structural sheathing) > 2×3 on the flat to create a vent channel > sheathing/roofing as per usual.  Does anyone know where this article is at?