Hi Tony, solid argument there based on the cardboard guitar outcome however the level of sustain would differ based on wood density and you would have to wonder why Gibson can get so many different sounds out of the same pickup configurations across their various body shapes. For example anyone can pick a Les Paul with their eyes closed and same goes for SG yet they sound distinctly different. Likewise when compared to Explorer and Flying V where the latter has least amount of wood and therefore sounds much brighter if not brittle when compared back to the standard old LP. Most Strats have so much empty space underneath their pick guards and that may lend weight to your theory as the pickups are mostly floating and not attached to the timber. We can expand the topic to include semi hollow bodies where the amount of timber density would be reflected in the overall tone and sound. And finally, if we consider the carbon fibre Steinbergers they had a unique sound due mostly to their composite structure not just from the EMG's installed on top.