From my experience as an SEO for a large eCommerce site (our own products), I tend to think that Google has a way of recognizing eCommerce site from purely informational ones and takes that into consideration when analyzing content.
As you say Chris, many producers will distribute their catalogs to all their dealers and they in turn will put those online. The same happens with our products here. Our dealers use the very description we provide them with and no one has ever been penalized for that.
As said, I personally think that Google takes the intent of your site (eCommerce, informational etc. ) into consideration when slapping duplicate content penalties.
Having said that, i have no data to back up that claim so go easy on me, it's only based on my gut feeling and practical observations.
